The present teachings provide simplified and intuitive control of a manipulator arm on a remote vehicle. The present teachings also provide simplified and intuitive control of manipulator arm such as a backhoe for digging remotely or in a typical cab-operated scenario.
Operating a manipulator arm with several degrees of freedom can be a complex task and can be cumbersome when controlling each joint individually. To ease demands on an operator, “fly the gripper” and “fly the head” routines have been developed, allowing an operator to specify x, y, and z gripper velocity components using, for example, a joystick. “Fly the head” control schemes work essentially the same way as “fly the gripper” control schemes, the only difference being that it is a head on the manipulator arm that is driven, not a gripper. Joint velocities for the specified components are computed and then executed to achieve the desired gripper velocity. To accomplish this, a forward kinematic map and Jacobian matrix can be computed for the manipulator arm, for example as described in Johnson, et al., Manipulator Autonomy for EOD Robots, the disclosure of which is incorporated herein by reference in its entirety. Fielded control schemes such as “fly the gripper” and “fly the head” allow a remote vehicle operator to move one point of an arm in the remote vehicle in Cartesian space, but without the ability to control the manipulator arm's link locations during this operation.
In an operational scenario, an operator may find himself needing to bend the arm in a specific way to avoid obstacles while reaching a desired target with, for example, a gripper located on the manipulator arm. Thus, the operator needs to control the manipulator arm's link locations during the operation, which cannot be accomplished with existing “fly the gripper” and “fly the head” control schemes. Another drawback to these existing control schemes is that an operator has no way of driving the remote vehicle chassis while moving its manipulator arm. The ability to simultaneously control these two actions would be extremely helpful in performing digging and dragging tasks, which are commonly performed by EOD operators looking for command wires.
A controller previously developed by Robotic FX uses an arm that is somewhat morphologically similar to a robot arm to control the robot arm, being morphologically similar in that it has the same number of joints. The Robotic FX controller arm can be manipulated to cause a manipulator arm of an associated remote vehicle to be similarly manipulated, including relative positioning of the joints and a head an/or gripper of the remote vehicle manipulator arm. The Robotic FX manipulator arm controller has a constant “home” position, with variation of the joint angles from the home position being mapped to joint velocities. When the operator removes his hand from the Robotic FX controller, the arm springs back to its home configuration while the robot's manipulator arm maintains its position.
The difference between a controller in accordance with the present teachings and the Robotic FX controller is the state that is being controlled. The Robotic FX controller controls the velocity of each joint rather than its position, whereas present teachings control a position of each joint. Further, the Robotic FX controller can only be moved to a limited degree from its home position, and the farther away the master arm is from home, the faster the robot manipulator arm moves. This type of control does not provide the operator with knowledge of the robot manipulator arm's existing physical configuration (position). Thus, when performing tasks without line of sight to the controlled remote vehicle manipulator arm, the operator can easily loose track of arm geometry and become confused regarding the motion that control inputs will produce.
The Robotic FX controller employs springs to return the master arm to its home position and employs stops to prevent over-rotation. The Robotic FX controller is designed to be utilized with a standard base control station by plugging a device including the master arm into a base control station, and thus it does not include a controller that can drive the remote vehicle chassis.
The present teachings provide a controller for controlling a remote vehicle manipulator arm, the controller comprising a master arm morphologically the same as or similar to the remote vehicle manipulator arm, the master arm comprising two or more links connected to each other by joints, each joint comprising a slip clutch and a sensor for measuring a joint angle. An operator manipulates the master arm to control the remote vehicle manipulator arm such that a position of each manipulator arm joint is controlled based on a position of each master arm joint.
The present teachings also provide a controller for controlling a remote vehicle manipulator arm, the controller comprising: a housing; a master arm mounted to the housing and comprising the same number of links and joints as the remote vehicle manipulator arm, the links being connected to each other by joints, each joint comprising a sensor for measuring a joint angle; a drive controller mounted to the housing and configured to allow an operator to drive the remote vehicle while the operator controls the manipulator arm with the master arm; and at least one additional input device configured to allow control of aspects the remote vehicle's manipulator arm aside from its position.
The present teachings further comprise a method for controlling a remote vehicle having a manipulator arm comprising two or more manipulator arm links connected to each other by manipulator arm joints. The method comprises: controlling the manipulator arm by manipulating a master arm that is morphologically similar to or the same as the manipulator arm, the master arm comprising two or more master arm links connected to each other by master arm joints. The position of each manipulator arm joint is controlled based on a position of each master arm joint.
Objects and advantages of the present teachings will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present teachings. The objects and advantages of the present teachings can be realized and attained by means of the elements and combinations particularly pointed out in the appended claim.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present teachings, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the present teachings and together with the description, serve to explain the principles of those teachings.
Reference will now be made in detail to exemplary embodiments of the present teachings, examples of which are illustrated in the accompanying drawings.
The present teachings include a remote vehicle controller providing full and intuitive control of at least a manipulator arm on a controlled remote vehicle such as, for example, a PackBot® EOD robot. Full and intuitive control can be achieved in accordance with the present teachings by providing a master arm on the remote vehicle controller that is morphologically the same as or similar to the manipulator arm on the remote vehicle. Upon altering the position of the master arm on the controller to a given configuration, the remote vehicle manipulator arm can be driven to achieve a matching configuration. This can be accomplished by accurate scaling of the remote vehicle controller's master arm to the remote vehicle's manipulator arm, measuring angles of the joints of the controller master arm, and implementing slip clutches at each joint.
Translation of controller master arm position to remote vehicle manipulator arm position can be achieved as follows. The controller master arm can be calibrated to the remote vehicle manipulator arm initially and, in accordance with various embodiments, periodically thereafter. A microcontroller within the remote vehicle controller housing can continuously receive voltage output from a potentiometer at each joint, and determine an exact angle of each joint based on that voltage output. There is a linear correlation between the position of a potentiometer and its output voltage, which can be mapped to an absolute angle of a joint. A value corresponding to the absolute angle for each joint of the master arm can be sent to the remote vehicle, and the remote vehicle can move its manipulator arm in a known manner based on the sent value to mimic the position of the master arm. In certain embodiments of the present teachings, the remote vehicle also avoids self-collision (e.g., collision of the arm with the remote vehicle chassis or a payload thereof) while achieving the desired manipulator arm configuration.
In certain embodiments of the present teachings, a height of the remote vehicle controller housing can be scaled to match or represent a height of remote vehicle's manipulator arm from the ground. Thus, when the remote vehicle controller rests on, for example, a table surface, touching a controller master arm gripper, head, or other functional attachment to the table surface will translate to touching a remote vehicle's manipulator arm gripper, head, or other functional attachment to the ground (given a generally flat ground surface). Accurate vertical offset of the remote vehicle controller's master arm in accordance with the present teachings can be achieved by physical sizing of the controller housing or by revising calculations in control software as would be understood by those skilled in the art.
The remote vehicle controller comprises a housing having front, rear, left, and right sides. The housing also has a top surface on which switches, a master arm, and a drive controller can be mounted.
An exemplary embodiment of a master arm is illustrated in
In accordance with various embodiments, a second camera such as a drive camera can be mounted at a base of the manipulator arm and can face in a forward direction of the remote vehicle but, in certain embodiments, can be capable of panning to follow a direction of the remote vehicle's manipulator arm. Both cameras (attack and drive) can be used when operating grippers in an EOD scenario. By manipulating its position on the master arm, a controller in accordance with the present teachings can be used by an operator or in an autonomous manner to aim the attack camera of the remote vehicle manipulator arm (e.g., to remain focused on a gripper in an EOD robot).
In accordance with certain embodiments such as the illustrated exemplary embodiments, a first joint of the master arm can have a single degree of freedom and comprise a potentiometer or other device for measuring the rotational position of the first joint. The first joint in the embodiment of
In certain embodiments, the second, third, and fourth joints of the master arm and the corresponding joints of the remote vehicle's manipulator arm can have a single degree of freedom. If the joints of the remote vehicle's manipulator arm have more than one degree of freedom, the present teachings contemplate the joints of the associated controller master arm also having more that one degree of freedom.
In accordance with certain embodiments, the remote vehicle manipulator arm and the controller master arm can have, overall, six degrees of freedom, which can be achieved using six independent single degree-of-freedom joints—none of which are redundant. The six joints can include the first through fourth joints illustrated in
Using a controller master arm that is morphologically the same as or similar to an arm being manipulated can allow novice operators to quickly and accurately perform complex manipulation tasks in an intuitive manner. The master arm can optionally comprise representative portions that represent attachments to the remote vehicle manipulator arm, such as a head and a gripper, to provide the operator with a more realistic model of the remote vehicle manipulator arm that he is controlling.
As depicted generally in
The controller can also comprise one or more switches allowing control of the remote vehicle, and particularly allowing control of aspects the remote vehicle's manipulator arm aside from its position. In certain embodiments, the switches can control, for example, opening and closing a gripper, rotating the gripper, selecting among one or more cameras such as drive and attack cameras, zooming the camera(s), and turning a remote vehicle brake on and off. The remote vehicle brake can control every actuator on the arm and can be employed as a safety measure (e.g., when a person is working around the remote vehicle) or to conserve power. The present teachings contemplate a variety of locations for the switches, for example on a top surface of the housing as illustrated, on the master arm, and/or on the drive controller. The switches can be, for example, positioned on the top and sides of the master arm and/or the drive controller in one or more ergonomically correct positions for activation of the switches while manipulating the master arm and/or the drive controller, in a manner similar to known flight simulator joysticks.
In various embodiments, the controller comprises a drive controller allowing an operator to drive the remote vehicle while manipulating the master arm. The drive controller can comprise, for example, a two degree-of-freedom analog joystick as illustrated in
In certain embodiments of the present teachings, the master arm can be disposed on the housing top surface such that it faces in another direction that that shown in
The present teachings contemplate using a controller in accordance with the present teachings to cause a gripper on the remote vehicle's manipulator arm to dig by scraping the gripper along the ground surface. The operator can achieve such a digging motion via a controller in accordance with the present teachings by manipulating the controller master arm such that its gripper scrapes along a surface of a table or other structure on which the controller housing rests. For such an operational scenario, it is particularly advantageous if a height of the remote vehicle controller housing can be scaled to match or represent a height of remote vehicle's manipulator arm from the ground as disclosed above.
A controller and method in accordance with the present teachings can also be used for remote control of other devices or vehicles such as, for example, a backhoe. A backhoe can comprise a piece of excavating equipment or digger including a digging bucket on a distal end of a two-part articulated arm. The bucket and two-part arm are typically mounted on the back of a vehicle such as a tractor or front loader, but could alternatively be mounted on a remotely-controlled vehicle such as a robot. The section of the two-part arm closest to the vehicle is known as the boom, and the section of the two-part arm that carries the bucket is known as the dipper. The boom is typically attached to the vehicle via a pivot known as a kingpost, which can allow the two-part arm to slew left and right, usually through an angle of about 200 degrees.
When an operator controls a backhoe vehicle from a location other than its cab, the present teachings consider the backhoe vehicle to be a remote vehicle because it is being controlled remotely.
An exemplary embodiment of a controller equipped with a manipulable backhoe-like master arm is illustrated in
In certain embodiments, a camera (not shown in
In accordance with certain embodiments, a first joint of
The first and second joints of the master arm and the corresponding joints of the backhoe can have a single degree of freedom. As stated above,
In the embodiment of
As depicted generally in
The controller can also comprise one or more switches allowing remote control of certain functions relevant to backhoe operation, for example selecting among one or more cameras if available, zooming the camera(s), turning a backhoe brake on and off, and engaging and disengaging stabilizer bars that are commonly engaged during backhoe operation.
In various embodiments, the controller also comprises a drive controller allowing an operator to remotely drive a vehicle on which the backhoe is mounted, while manipulating the backhoe two-part arm and bucket with the master arm. The drive controller can comprise, for example, a two degree-of-freedom analog joystick as illustrated in
In various embodiments of the present teachings, an additional input device can be employed for OCU input, for example a laptop keyboard as illustrated in
If the joints of the backhoe have more than one degree of freedom, the present teachings contemplate the joints of the associated controller master arm also having more that one degree of freedom.
In an exemplary digging process utilizing the controller embodiment illustrated in
In embodiments employing a backhoe-like master arm to be used in digging operations, a height of the controller housing is preferably (but not necessarily) scaled to match or represent a height of actual backhoe from the ground so that, when the controller housing rests on a surface such as a table surface, touching the bucket of the master arm to the table surface will translate to touching the actual backhoe's bucket to the ground (given a generally flat ground surface). Accurate vertical offset of the master arm can be achieved by physical sizing of the controller housing or by revising calculations in control software as would be understood by those skilled in the art.
In accordance with certain embodiments, a backhoe-like master arm such as that illustrated in
Although real-time control of an actual manipulator arm with a morphologically similar master arm may not be fully achievable, certain embodiments of the present teachings can approach real-time control by employing damping, e.g., mechanical damping via slip clutches, to slow movement of the controller master arm to match the speed capabilities of the manipulator arm on the remote vehicle. Alternatively or additionally, the present teachings contemplate allowing an operator to manipulate the controller master arm to a variety of preset poses, which are then matched by the remote vehicle manipulator arm at achievable speeds.
The present teachings contemplate the operator simultaneously utilizing the drive controller and the master arm to move the remote vehicle and its arm simultaneously, for example for digging. When digging, it is common to drive the vehicle forward, reach forward (away from the vehicle) with the manipulator arm to engage the ground, and pull the portion of the manipulator arm (e.g., a gripper or a backhoe bucket) engaging the ground backward (toward the vehicle) in a digging motion. As the portion of the manipulator arm is engaging the ground, it may be desirable to drive the vehicle backward and continue dragging the manipulator arm along the ground, for example when looking for command wires.
Other embodiments of the present teachings will be apparent to those skilled in the art from consideration of the specification and practice of the teachings disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the present teachings being indicated by the following claims.
This application claims priority to U.S. Provisional Patent Application No. 61/220,128, filed Jun. 24, 2010, titled Remote Vehicle Controller, the content of which is incorporated herein in its entirety.
Number | Date | Country | |
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61220128 | Jun 2009 | US |