Ford Motor Company Limited

Gard, Inc.

Veljko Milenkovic

Bernard Huang

Nathaniel L Field

John M Buday

Hossein Nivi

Lawrence B Holmes

Shimshon Shmuter

Loo Ming

Bernard Stevens

George W McClure

A method and system for correcting a programmed robot manipulator path to compensate for variability of the location of a succession of workpieces includes the steps of sensing and measuring path offsets between the idealized workpiece location and the actual location of the workpiece at a plurality of waypoints, converting the measured offsets into translations and rotations of the workpiece by multiplying a matrix comprised of the offset measurements by a previously prepared conversion matrix, correcting the coordinates of waypoints within the preprogrammed path by applying the translations and rotations to such coordinates, transforming the corrected preprogrammed path coordinates into machine control coordinates, and providing a controller for the robot manipulator with such machine control coordinates.

Method and system for correcting a robot path

The end of a robot arm includes two links, a first or inner link supported rotatably about a central axis and an end link at which a tool is carried. Located between the links are a rod and a tube whose longitudinal axes are concentric. Each of four gimbal rings is used as a member of a universal joint that connects the links, the rod and the tube. The links are connected by two universal joints in series, and the rod connects these joints. The links are also connected by two other universal joints in series and the tube connects this second pair of joints. The first and second pairs of universal joints connected in series are connected to one another in parallel. Gimbal rings rotatably supported on the tube and on the links for angular movement about yaw axis provide rotational support for the links and the connecting rod about the pitch axis. Actuating rods connected to the inner set of gimbal rings produce articulation of the wrist about these axis when the rods are actuated. Angular pitch displacement and angular yaw displacement are equalized between the inner set of gimbal rings and the outer set of gimbal rings by tension members. Alternatively, continuously meshing gear wheel portions equalize yaw and pitch rotational displacement, respectively.

Non-singular industrial robot wrist

A method for generating a path to be followed by the end effector of an industrial robot includes defining the location of points on the path, recording the coordinates of the points in cartesian space, determining the slope of the path at each of the taught points with reference to a code that defines the nature of the path in the vicinity of each point, calculating the direction vector representing the slope at each taught point, locating the position and slope of a point midway between successive taught points, connecting the taught points and the midpoints with a circular arc whose slope is equal to the slope at the taught points and midpoints, and generating points between the taught points with reference to the desired velocity of the end effector at each of the generated points on the path to be traversed.

Automated curvilinear path interpolation for industrial robots

The large rotational inertia applied to a driveline component during normal driving conditions is simulated in a test stand that contains a component that driveably connects an input motor and an output motor. A computer repetitively executes an algorithm that produces a commanded torque signal which is supplied as a control signal to the motor drive of one of the electrical motors to produce an output within that motor equal to the commanded torque. The control system applies to the powertrain component under test an inertia that simulates the actual vehicle inertia. The target state of the system, when the vehicle inertia is applied, is completely defined from information known when the component being tested has substantially less inertia applied.

Computer simulated inertia for motor vehicle powertrain testing

The end of a robot arm includes two links, a first or inner link supported rotatably about a central axis and an end link on which a tool is carried. Located between the links are a ring and a tube whose longitudinal axes are concentric. Each of four gimbal rings is used as a member of a universal joint that connects the links, the ring and the tube. The links are connected by two universal joints in series, and the ring connects these joints. The links are also connected by two other universal joints in series and the tube connects this second pair of joints. The first and second pairs of universal joints connected in series are connected to one another in parallel. Gimbal rings rotatably supported on the tube and on the links for angular movement about the yaw axis provide rotational support for the links and the connecting rod about the pitch axis. Actuating rods connected to the inner set of gimbal rings produce articulation of the wrist about these axis when the rods are actuated. Angular pitch displacement and angular yaw displacement are equalized between the inner set of gimbal rings and the outer set of gimbal rings by tension members.

Hollow non-singular robot wrist

A method to avoid excessive rotational speeds, of the axes of a robot wrist, that result in the vicinity of a singularity in the path defined by consecutive points along which a tool held by a three-axis wrist mechanism of the robot moves. The speeds of the first and third axes are reduced within the allowable range of rotational speed for these axes, generally defined by the robot manufacturer, while maintaining constant the rotation about the intermediate or second joint. The rotational speed about each of these axes is determined as the tool moves between successive points on the path. Then, if necessary, the rotation of the second joint is decreased while maintaining constant the speeds about the first and third axes. Finally, the tool is maintained on the path by rotating the position of the tool without altering the reduced speeds of rotation about the axes.

Method to avoid singularity in a robot mechanism

A motion control system includes a single stage gear reducer and power screw, a brushless variable-speed electric motor with position and velocity sensing instrumentation, a solid state power amplifier, and a programmable controller. During operation an absolute positional reference is established when the slide actuates a non-contacting limit switch to signal that the slide is within less than one motor revolution of the correct starting point. A memory accessible by a microprocessor has paired values of velocity and position stored in a table representing ideal such values for deceleration portions of the motion cycle. Alternatively, the microprocessor computes each new value of position and velocity in real time as required to update the velocity commands sent to a comparator. The comparator compares the predetermined slide position to the actual slide position and signals the microprocessor that a change in output to the motor power supply is required. A digital to analog converter converts the motor velocity signal that issues from the microprocessor to a variable d.c. voltage whose magnitude varies over a range that determines the sense of direction and speed of the drive motor.

Control for automatic machine tool drive

A system for stacking into containers flat articles received in a shingled stream, the flat articles being disposed essentially normal to the bottoms of the containers into which they are stacked; mechanism is provided for rapidly diverting the shingled stream of flat articles from the rear of a just filled container to the front of the next empty container in a line of moving containers to feed flat articles into successive containers without interruption; containers having elongated slots in the ends are provided to facilitate the rapid shifting of the article stream from container to container in a line of containers; there also is provided a mechanism to generate a gap in the shingled stream of flat articles to facilitate transfer of the stream from a filled container to an empty container; there further is provided mechanism for diverting the shingled stream of flat articles before it reaches the containers to sample the flat articles or to reject the flat articles should they be defective; also provided are novel container conveyor systems for conveying containers to the loading station to accommodate the stacking mechanism.

Growing community of inventors

Birmingham, MI, United States of America

Veljko Milenkovic