BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is an illustration of an exemplary vehicle having a closure member controlled by a closure system;
FIG. 1B is a rear view illustration of the exemplary vehicle showing non-contact sensors for sensing obstacles in the path of the closure member;
FIG. 1C is a block diagram of an exemplary controller for controlling a closure member;
FIG. 2 is a graph showing an exemplary conventional speed control profile and an adaptive speed control profile having a higher cycle rate in accordance with the principles of the present invention;
FIG. 3 is a graph showing exemplary signals for sensing an obstacle in the path of a closure member and collision of the closure member with the obstacle;
FIG. 4 is a flow diagram of an exemplary process to monitor for an obstacle in the path of a closure member and adaptively changing the speed of the closure member in response to sensing an obstacle in the path of the closure member;
FIG. 5 is a graph showing a conventional speed control profile and an adaptive speed control profile in responding to sensing an obstacle in the path of a closure member;
FIG. 6 is a graph showing a number of speed control profiles using different values of a proportionality constant in an exemplary linear speed control algorithm; and
FIG. 7 is a flow diagram of a more detailed process for controlling a closure member in accordance with the principles of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1A is an illustration of an exemplary vehicle 100 having a vehicle body 102 and closure member controlled by a closure system. In this embodiment, the closure member is a lift gate 104 that is coupled to the vehicle body 102 by one or more hinges 106. Although a lift gate is shown as the closure member in this embodiment, it should be understood that the principles of the present invention may be applied to any rotational or non-rotational closure system of a vehicle. Such closure members may include a trunk, lift gate, sliding door, window or other powered device. Still yet, closure systems that are used on structures other than vehicles are contemplated in accordance with the principles of the present invention. Such structures may include, but are not limited to, trains, airplanes, boats, buildings, or other structures. Closure members of these structures may include doors, windows, ladders, or other powered devices.
The lift gate 104 is controlled by a controller 108 for moving the lift gate 104 into open and closed positions. The controller 108 may drive a motor 110 that causes a cylinder 112 to push and pull on the lift gate 104. In one embodiment, the motor 110 is a hydraulic pump. Alternatively, the motor may be any other electromechanical actuator for causing the lift gate 104 to open and close. If the closure member is a window or other closure member, an electromechanical motor, such as a direct current (DC) or alternating current (AC) motor, may be utilized in accordance with the principles of the present invention. While the controller 108 is shown as a separate unit, the functionality may be integrated into processors used in other parts of the vehicle or structure.
Non-contact sensor 114a/114b may be located at the rear of the vehicle. In one embodiment, the non-contact sensors may be any non-contact sensor. For example, the non-contact sensor may include capacitive, ultrasonic, optical, thermal or other non-contact sensor as understood in the art. As shown, the non-contact sensor 114a/114b may output an incident signal 116a and receive a reflected signal 116b in response to the incident signal 116a reflecting from an obstacle 118 in the path of the lift gate 104.
In terms of being “in the path” of the closure member, an obstacle that is estimated to be in the direct path or relatively near the path of the closure member may be determined to be “in the path” of the closure member. If a sensing element (e.g., capacitive) that is less accurate is used, then being in the path may be less accurate than using a more accurate sensing element (e.g., optical). It should be understood that if a passive sensing element, such as a capacitive sensing element, is used then there are no incident and reflection signals 116a and 116b.
If the non-contact sensor 114a/114b senses an obstacle to be within the path of the closure member, then an obstacle signal 120 may be generated from the sensors and communicated to the controller unit 108. The obstacle signal may simply be a change in signal level being outputted from the obstacle sensor 114a/114b. In other words, if an obstacle signal is substantially OV and transitions to 5V, for example, that transition is indicative of an obstacle signal being generated.
FIG. 1B is a rear view illustration of the exemplary vehicle showing the non-contact sensor 114a/114b for sensing obstacles in the path of the closure member. As shown, obstacle sensor 114a/114b is disposed on the rear of the vehicle. The obstacle sensor 114a/114b may be positioned on a rear bumper of the vehicle or located elsewhere, such as on the closure member (e.g., lift gate 104), vehicle body 102, or otherwise. It is also contemplated that multiple sensors can be used. For example, it is contemplated that a sensor can be mounted on a lift gate and also on the vehicle body. If located on the rear bumper 122, then the obstacle sensor 114a/114b may be used to sense when an obstacle is located in the path of the lift gate 104 both while opening and closing. Alternatively, if the obstacle sensor 114a/114b is located on the inside of the lift gate 104, then it may be limited to use while closing the lift gate 104.
The obstacle sensor 114a/114b as shown is formed of a transmitter to transmit the incident signal 116a and a receiver to receive the reflected signal 116b, as understood in the art. One or more of the same and/or different non-contact sensors that are capable of sensing an obstacle in the path of the closure member during opening and closing operations may be utilized in accordance with the principles of the present invention.
FIG. 1C is a block diagram of an exemplary controller for controlling a closure member. The controller 108 may include a processor 124 that executes software 126. The processor 124 may be a general-purpose processor, application specific integrated circuit (ASIC), digital signal processor (DSP), or any other device capable of executing the functionality of controlling the closure member. A memory 128 and input/output (I/O) unit 130 may be in communication with the processor 124. The memory 128 may be used to store software and parameters to operate the closure system and the I/O unit 130 may be used to drive an actuator for moving the closure member.
The software 126 may include control algorithms for controlling operation of one or more closure members in accordance with the principles of the present invention. It should be understood that the processor 124 may include one or more processors operating together or independently for controlling one or more closure members.
FIG. 2 is a graph showing an exemplary conventional low speed control profile and an adaptive speed control profile having a higher cycle rate than the conventional low speed control profile in accordance with the principles of the present invention. Conventional low speed control profile 202 is shown for comparative purposes. The conventional low speed control profile transitions from a speed of 0 to a speed of y between times T0 and T1. Upon approaching closure or full open of the closure member at time T2, the speed transitions from a speed of y to y/2 at time T3. The conventional low speed control profile 202 continues to move the closure member at a speed of y/2 until time T4, whereupon the speed transitions back to 0 at time T5, The closure travel or open travel cycle is complete at that time.
Continuing with FIG. 2, an adaptive speed control profile 204 provides for higher open and close speeds relative to those of the conventional low speed control profile and low operation cycle times under normal operation. And, in the event of an obstacle being sensed in the path of a closure member, the adaptive speed control profile 204 allows for normal or even reduced pinch forces through a “look-ahead” reduction in velocity (see, FIG. 5). The algorithm is adaptive in that it is capable of changing operation in response to a changing environment during operation of the closure system. In the event that an obstacle sensor fails due to damage or otherwise, the controller may use a conventional or standard low speed control profile, which generally prevents excessive pinch forces.
As shown, the adaptive speed control profile 204 transitions between speeds of 0 to 2 y between times T0 and 0.5 T1. This means that the speed of the closure member ramps to twice the speed using the adaptive speed control profile than the standard low speed control profile 202 in half the time. Similarly, the speed of the closure member transitions between times T6 and T7 from a speed of 2 y to y/2, which is the same speed as the closure speed produced by the standard low speed control profile 202 at time T3. The adaptive speed control profile 204 continues at speed y/2 until time T8, where it transitions to a speed of zero at time 0.5 T5. The cycle time of the adaptive speed control profile 204 operates in half the operation cycle of the standard low speed control profile 202. It should be understood that alternative speed control profiles may be utilized in accordance with the principles of the present invention that are faster or slower than the standard low speed control profile 202 and provide for obstacle detection speed transitions.
FIG. 3 is a graph 300 showing exemplary signals for sensing (i) an obstacle in the path of a closure member, and (ii) a collision of the closure member with the obstacle. As shown, an obstacle signal 302 initially does not sense an obstacle in the path of a closure member and outputs a 0 volt signal. At time TS, an obstacle in the path of the closure member is sensed, which causes a transition of the obstacle signal 302 to a voltage V. This transition may be considered to be a generation of an obstacle signal. It should be understood that this obstacle signal 302 is one embodiment and that other or alternative signaling may be utilized to indicate that an obstacle is being sensed in the path of a closure member. The obstacle signal 302 and/or collision signal 304 may be digital or analog depending on the configuration of the electronics.
After the obstacle is sensed indicated by the obstacle signal 302 transitioning to a voltage V, a collision by the closure member may be sensed by a collision sensor, as understood in the art. The collision causes a transition of the collision signal 304 to occur at time TC to a voltage V. This collision signal 304 may be used by a controller to stop or reverse the closure member to avoid injuring or damaging the obstacle, as is conventionally performed.
FIG. 4 is a flow diagram of an exemplary process 400 to monitor for an obstacle in the path of a closure member and adaptively changing the speed of the closure member in response to sensing an obstacle in the path of the closure member. The monitoring process 400 starts at step 402. At step 404, a path of a closure member may be monitored for an obstacle. At step 406, an obstacle signal may be generated in response to sensing an obstacle. In generating the obstacle signal, a transition from low to high voltage may be generated, thereby indicating that an obstacle is being sensed in the path of a closure member. At step 408, the closure member may be driven at a first speed while the obstacle signal is not being generated and, in response to the obstacle signal being generated, the speed of the closure member may transition to a second speed, slower than the first speed. The monitoring process ends at step 410.
FIG. 5 is a graph 500 showing a conventional low speed control profile 502 and adaptive speed control profile 504 in responding to an obstacle in the path of a closure member. A standard speed control profile 502 is shown with an adaptive speed control profile 504 to differentiate responses to sensing an obstacle in the path of the closure member and to contacting an obstacle by the closure member. As shown, the standard speed control profile 502, which includes obstacle collision sensing, initially ramps up to a speed of y and progresses along at that speed until a collision with an obstacle occurs, whereupon the closure member is stopped by the speed dropping sharply to 0.
The adaptive speed control profile 504, by contrast, ramps up to a speed of 2 y and progresses along until time T6, whereupon a non-contact sensor identifies an obstacle in the path of the closure member. This “look-ahead” capability detects the presence of the obstacle in the path of the closure member prior to colliding with the closure member. This sensing creates a “region of awareness” ΔT that is relative to the “look-ahead” range of the sensing element. In the region of awareness, the closure system is aware of the obstacle, and has time to react before contact. The closure system may reduce its speed at a rate of change that is proportional to the distance from the obstacle. In one embodiment, the rate of change is linear. Alternatively, the closure system may use a non-linear controller to change the rate of speed relative to the distance from the obstacle. As shown, the adaptive speed control profile 504 transitions from a speed of 2 y at time TS substantially linearly to a speed of y/2 at time TC. At time TC, an obstacle collision is detected by the closure system and the closure member is stopped. It should be noted that the adaptive speed control profile 504 is moving at a speed half of the speed of the standard low speed control profile 502 when the collision of the closure member occurs with the obstacle at time TC. This slower speed is considered to be a “soft” collision between the two objects. Because the speed at the time of collision is reduced by the use of the adaptive speed control profile 504, pinch forces are significantly reduced and stress on the closure system by either contacting an obstacle at a speed of y (i.e., twice the speed) or a high speed reversal is also decreased. Reducing the stresses on the closure system potentially extends operational life of the closure system.
In reducing the speed of the closure member during the region of awareness, various speed distance algorithms may be utilized. These algorithms may be linear or non-linear, depending on the control desired and the closure member being controlled. In one embodiment, the speed distance algorithm may be defined by the following equation:
V=V1×(1−K×X/X1), where
- V=instantaneous speed at X;
- V1=initial speed;
- X1=initial distance from obstacle;
- X=instantaneous distance; and
- K=proportionality constant
Although not shown in the adaptive speed control profile 504, if the obstacle is removed from the path of the closure member before the closure member is stopped, then the system may utilize the speed control algorithm as defined above to speed up the closure member until it reaches the maximum speed (e.g., 2 y) to continue along its path of travel. It should be understood that a different control algorithm may be used to increase the speed of the closure member, such as a ramp or spline used at the start of movement of the closure member from time T0. Once the closure member has completed its travel, the closure member may be cinched or latched into place and the closure system may be put into a sleep mode or otherwise until a power cycle to move the closure member is initiated again. In one embodiment, see FIG. 6, a minimum speed Vf may be set such that the slowest speed allowed by the system is Vf. This minimum speed Vf may be configured using software, and is slow enough to reduce pinch force. For example, minimum speed Vf may be set to 5 or other value less than the slowest contact speed of conventional closure systems. Regardless of the proportionality constants, closure member may continue to move at speed Vf until it contacts the obstacle and the braking begins.
FIG. 6 is a graph showing a number of speed control profiles 602, 604, 606 and 608 with different proportionality constants. As shown, the various speed control profiles 602-606 can be generated through the manipulation of the proportionality constant K, thereby allowing for behavior of the closure system to be configured as desired. In this example, the curves each start with an initial velocity of V1=20 and initial distance X1 to the obstacle of 40. The proportionality constant K is set at 0.5 for curve 600, 1.0 for curve 604, 2.0 for curve 606, and 3.0 for curve 608.
When K=0.5, transition of the initial speed from 20 decreases relatively slowly, such that the speed is 10 when contacting the obstacle. If the proportionality constant is higher than 1, then the closure member ramps down until it reaches a minimum speed Vf and contacts the obstacle, as shown by curves K=1, K=2 and K=3. It should be understood that a proportionality constant may be selected by the manufacturer as desired, or the manufacturer may provide operators with control over the proportionality constant K via a switch, knob, or other control mechanism as understood in the art. In providing the control to an operator, rather than describing that control mechanism as affecting a proportionality constant K, it may be described as child or adult setting, for example. For example, a child setting would not avoid the closure member from contacting the obstacle (i.e., K>1.0). However, it would prepare the closure member for contacting at a greater distance from the obstacle. On the other hand the adult setting would allow the closure member to provide closure to the obstacle before Vf.
FIG. 7 is a flow diagram of a more detailed adaptive speed control process 700 for controlling a closure member in accordance with the principles of the present invention. The adaptive speed control process 700 starts at step 702. At step 704, the process waits for a command to initiate a power cycle for controlling the closure member. The command may be given by a driver of a vehicle by pushing a button or switch in the vehicle or on a remote control, for example. At step 706, a determination is made as to whether a power cycle has been initiated. If not yet initiated, then the process returns to step 704 until a power cycle has been initiated. Upon determination that the power cycle has been initiated at step 706, the process continues at step 708, whereupon obstacle detection is enabled.
At step 710, a non-contact sensing element or sensor is checked. If it is determined at step 712 that the sensing element is malfunctioning, then the process continues at step 714, where a warning that the sensing element is malfunctioning is reported. In the case of the closure system being in a vehicle, the warning may be provided to a driver of the vehicle via a visual and/or audio signal. At step 716, the closure system uses a standard (low) speed control/obstacle detection method. This operation may be used to operate the closure member as shown in FIG. 5, in one embodiment. Upon completion of the operation of opening or closing the closure member, the process continues at step 704.
If it is determined that the non-contact sensing element is not malfunctioning at step 712, then at step 718, prior to moving the closure member, the sensing element senses the path of the closure member prior to a closure system moving the closure member. A determination is made at step 720 as to whether the non-constant sensor senses an obstacle in the path of the closure member. If so, then at step 722, a determination is made that an obstacle is in the path of the closure member and the closure system prevents the closure member from moving. The process continues at step 704.
If the obstacle sensor does not sense an obstacle in the path of the closure member at step 720, then the process continues at step 724 where the closure member begins a “power cycle” at a predefined speed. This may be seen on FIG. 5 as the adapted speed control profile 504 ramps from 0 to 2 y between times To and 0.5 T1, where the predefined speed reaches 2 y. It should be understood that other transitions or predefined speeds may be utilized in accordance with the principles of the present invention. At step 726, a control algorithm may be utilized for speed control. In one embodiment, the control algorithm is a PID controller. Other control algorithms may be utilized for controlling the speed of the closure member in accordance with the principles of the present invention. At step 728, the non-contact sensor may continue to sense for an obstacle that enters the path of the closure member. At step 730, a determination is made as to whether the non-constant sensor senses an obstacle in the path of the closure member. If not, then at step 732, a determination is made if the closure member has completed travel. If not, then the process may continue at step 724. Otherwise, if the closure member has completed travel, then the process may continue at step 734 and a “soft” stop algorithm may be applied, and the closure member is cinched and/or latched at step 736. The process repeats at step 704.
If at step 730, the obstacle sensor senses an obstacle in the path of the closure member, then at step 738, a measurements between the distance of the obstacle and the closure member is made. At step 740, speed of the closure member is decreased in accordance with a speed/distance algorithm. In one embodiment, the speed/distance algorithm may be that of the speed control profile described with respect to transition of the speed of the closure member in the region of awareness shown in FIG. 5. At step 742, a determination is made as to whether the obstacle has been contacted by the closure member. If not, the process may repeat back at step 730, where a determination is made as to whether the obstacle remains in the path of the closure member. If the obstacle is removed from the path of the closure member (e.g., a person or object moves out of the way of the closure member), then the depth of speed control algorithm may increase the speed to the maximum level (e.g., 2 y). If it has been determined at step 742 that the obstacle has been contacted by the closure member, then at step 744, the closure system may stop or reverse the direction of the closure member at step 744, and the process may stop or reverse at step 724. Accordingly, the specific flow or operations of the process 700 may be altered and accommodate the principles of the present invention.
The previous detailed description is of a small number of embodiments for implementing the invention, it is not intended to be limiting in scope. One of skill in this art will immediately envisage the methods and variations used to implement this invention in other areas than those described in detail. The following claims set forth a number of the embodiments of the invention disclosed with greater particularity.
Patent Application
20070296242
