Unimation, Inc.

Torsten H Lindbom

Maurice J Dunne

William Perzley

Joseph F Engelberger

Wilbur N Roberts

Horace L Gardner

Donald W Munger

An industrial robot in which both a column which is pivotally mounted on a rotatable base member and a boom which is pivotally mounted on the upper end of the column are of hollow construction to provide a rigid lightweight structure capable of carrying substantial loads. The column is counterbalanced by a spring and the boom is counterbalanced by pneumatic cylinders on a movable carriage so that the major axes of the robot can be driven by relatively low energy driving sources. A simplified hand gear train is provided which is capable of carrying substantial loads and is easily serviced.

Low cost robot

Manipulator apparatus is provided with an energy efficient control arrangement. The control arrangement in a point-to-point mode of operation utilizes a servo valve to selectively admit fluid from a pressurized source to one end of a cylinder. A piston is slidably mounted within the cylinder and connected to move a manipulator arm that is movable in a plurality of axes. The servo valve is closed when a predetermined arm velocity is reached and a bypass valving arrangement is opened to interconnect the ends of the cylinder. At a predetermined position of the manipulator arm, the control arrangement closes the bypass valving arrangement and the manipulator arm is decelerated as the arm approaches the desired final position. The pressurized source includes an accumulator and two high pressure check valves that each connect a respective end of the cylinder to the accumulator when the pressure at the respective end of the cylinder exceeds the accumulator pressure to supply pressurized fluid to other axes of the manipulator. The control arrangement compares the deceleration of the arm with a reference table of scheduled points representing desired velocity at respective positions to selectively control the opening and closing of the bypass valving arrangement during deceleration. During repetitive work or repeat cycles of operation, the reference table is modified in accordance with adaptive procedures to provide accurate control of the deceleration of the arm and the point at which the bypass valve is closed to initiate the deceleration.

Manipulator apparatus with energy efficient control

A programmable manipulator is provided in which the manipulator arm is counter-balanced in all of its major axes and these axes are provided with low friction joints so that a relatively small force is needed to move the arm in each of its principal axes. A separate low power driving source is then used to move the arm during the teaching operation, this low power driving source being capable of developing the relatively small force needed to move the arm at low speed during the teaching operation, but being incapable of moving the arm at high speed or exerting a torque on said arm which will be potentially harmful to programming personnel. After the desired path has been taught, the manipulator apparatus is switched over to a playback mode wherein a second relatively high power source is employed to move the arm at relatively high speed during successive playback cycles. An interlock arrangement is provided for positively preventing the high power driving source from being used to move the arm during the teaching operation so that it is impossible for malfunctions in the control system or servo valves to cause a build-up of enough momentum in the arm to be harmful to the programming operator who may be in the path of such movement.

Safe programming system for industrial robots

A programmable automatic assembly system is provided which may be employed to assemble small parts. Each assembly station includes cooperating manipulator arms which are programmable to assemble parts on a centrally located work table. Improved facilities are provided for teaching the manipulator arms at each station, these facilities including a computer which assists the teaching operator in setting up the programs required for assembly of small parts to close tolerances. Each manipulator arm includes closed loop teach facilities for maintaining the arm at a previously located position during the teaching mode of operation. The computer is employed as a teach assist facility in performing a number of tasks during the teaching operation which are extremely difficult for the operator to perform manually. All of the assembly stations may be controlled during playback from a common disc storage facility so that the control circuitry and memory storage facilities at each manipulator are minimized.

Programmable automatic assembly system

A manipulator apparatus having a manipulator arm movable in a plurality of axes is programmed and taught to perform a desired sequence of operations over selected work paths. Basic control parameters relating to movement of the arm independent of the length and orientation of the work paths are programmed by a supervisor/programmer on the controls of a supervisory control unit. The control parameters represent manipulator work parameters and manipulator arm movement different than the taught work paths in a subsequent second teach phase. An operator/programmer in a teach phase proceeds to guide the manipulator arm over the predetermined work paths in contact with a work surface. The work paths are taught or programmed by the automatic recording into a main control memory of positional data. During the teach phase, the control parameters stored in the supervisory control unit are automatically recorded into the main control memory for each of the work paths in a predetermined relationship to the recorded positional data points. The recorded signals are utilized as command signals in subsequent playback cycles. Between sequential work paths in the overall work cycle or work path sequence, transfer steps corresponding to manipulator arm movement not in contact with the work surface are also taught by the recording of data into the main control memory during the teach phase.

Teaching arrangement for programmable manipulator

A programmable automatic assembly system is provided which may be employed to assemble small parts. Each assembly station includes cooperating manipulator arms which are programmable to assemble parts on a centrally located work table. Improved facilities are provided for teaching the manipulator arms at each station, these facilities including a computer which assista the teaching operator in setting up the programs required for assembly of small parts to close tolerances. Each manipulator arm includes closed loop teach facilities for maintaining the arm at a previously located position during the teaching mode of operation. The computer is employed as a teach assist facility in performing a number of tasks during the teaching operation which are extremely difficult for the operator to perform manually. All of the assembly stations may be controlled during playback from a common disc storage facility so that the control circuitry and memory storage facilities at each manipulator are minimized.

A manipulator apparatus having a manipulator arm movable in a plurality of axes is programmed to perform a desired sequence of operations over a desired path. The programming is accomplished by an operator manually moving the end of the manipulator arm over the desired path while encoders associated with each axis of the manipulator apparatus produce signals representing movement of the arm in each of the axes. The encoder signals are automatically recorded at predetermined increments of movement of the arm as command signals for controlling movement of the arm during a playback cycle. Recording of these command signals is controlled by a guide wheel which is positioned on the end of the arm during programming and is rotated by maintaining the wheel in contact with the work as the operator moves the manipulator arm over the desired path. Control pulses are generated for each predetermined increment of rotation of the guide wheel and these control pulses are employed to control recording of the encoder output signals. Weld cycle controls, weld speed controls and a manual record control are provided. The manual record control is actuated to record positions between welds wherein the end effector is moved between weld paths without the guide apparatus being in contact with the welding work surfaces. During programming, guide strips having tracks into which the guide apparatus is placed, may be positioned along the desired weld path by the operator. The recorded signals corresponding to the distances the arm is to be moved in each of said axes are utilized during a playback cycle to control drive apparatus for each axis, such as stepping motors, which are de-energized during the programming phase. During playback a welding tip or other implement is positioned in place of the guide wheel apparatus whereby the manipulator performs the desired operation over the programmed path at a predetermined, selectable speed independent of the programming speed. The recorded command signals are effective to drive pulse generation circuitry during playback to produce pulse trains that are supplied to the stepping motors so that they are moved at the required velocities to perform a weld over the programmed path.

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Brookfield, CT, United States of America

Torsten H Lindbom