Robot feature tracking devices and methods
AssigneeServo-Robot Inc.
InventorsJean-Paul Boillot, Denis Villemure
Life of this patent
Estimating the term…
Abstract
Motorized slides are inserted between the end of a robot arm and a robot tool/sensor arrangement to provide additional positioning ability. A control unit of the slides cooperates with the control unit of the sensor to maintain the tool correctly positioned over a feature while the robot arm moves following a programmed path. The control unit of the sensor has look-ahead and additional buffers from which corrected information is determined to compensate for robot teaching inaccuracies, calibration and robot arm response errors. A sensor with two distinct probing zones is used to get information about the position of the tool tip and of the feature to assist in calibrating the sensor/tool relation.
Claims20
A motorized slide assembly for providing additional positioning ability to a tool at an end of a robot arm, comprising:
- a slide arrangement having a base and a sliding element movable along a predetermined course relative to the base;
- a motor mounted onto the slide arrangement;
- a drive means connected to the motor for moving the sliding element along the course upon operation of the motor;
- a means for fastening the base of the slide arrangement to the end of the robot arm;
- and
- a means for fastening the tool onto the sliding element.
A motorized slide system for providing additional positioning ability to a tool at an end of a robot arm, comprising:
- a motorized slide assembly including:
- a slide arrangement having a base and at least one sliding element movable along a predetermined course relative to the base;
- at least one motor mounted onto the slide arrangement;
- at least one drive means connected to said at least one motor for moving said at least one sliding element along the course upon operation of said at least one motor;
- a means for fastening the base of the slide arrangement to the end of the robot arm;
- a means for fastening the tool onto said at least one sliding element;
- and
- at least one encoder operatively coupled to said at least one motor to provide motor positional information;
- and
- a control unit for the motorized slide assembly, including:
- a communication interface for receiving sensor related data;
- a I/O interface for receiving and transmitting synchronization signals;
- a CPU for controlling positions of said at least one sliding element;
- a memory;
- a servo-amplifier circuit for powering said at least one motor;
- a slides control for controlling said servo-amplifier circuit in response to the CPU and the motor positional information provided by said at least one encoder;
- and
- a bus circuit interconnecting the communication interface, the I/O interface, the CPU, the memory and the slides control together.
A compensation method for compensating errors made by a control unit of a robot sensor when evaluating a relation between a position of a robot guided tool behind the sensor and a position of a feature to be followed by the guided tool, comprising the steps of:
- recording position data generated by the sensor during a dry pass of the guided tool over the feature, the position data representing consecutive positions of the feature detected by the sensor;
- and
- subtracting the recorded position data from joint position errors computed by the control unit during a feature tracking operation where the guided tool is operated to process the feature.
A control unit for a robot sensor tracking a feature to be processed with a robot tool positioned behind the robot sensor, comprising:
- a sensor interface having a sensor control output and a video input;
- a memory connected to the sensor interface;
- a CPU connected to the sensor interface and the memory;
- and
- a communication interface connected to the CPU, the memory and the sensor interface, and having a communication port;
- wherein:
- the memory includes:
- a look-ahead buffer that stores a number of successive feature position data computed by the CPU from signals received at the video input, as a function of tracked successive positions reached by the robot sensor during displacement over the feature;
- and
- an additional buffer connected to the look-ahead buffer, that stores a number of the successive feature position data as a function of tracked successive positions reached by the robot tool;
- and the CPU has an operating mode causing a computation of a corrected position value required to maintain the robot tool correctly positioned over the feature by subtracting a current position of the robot tool and one of the position data stored in the additional buffer related to the current position of the robot tool from one of the position data stored in the look-ahead buffer related to the current position of the robot tool, and a transmission of the corrected position value through the communication port of the communication interface.
A robot sensor assembly for simultaneously detecting a position of a feature at a given look-ahead distance in front of a tool and a position of a tip of the tool, comprising:
- a sensor body;
- a bracket for side attachment of the sensor body to the tool;
- a first probe means attached to the sensor body and directed toward the feature in front of the tool, for providing surface range data along the feature whereby the position of the feature at the look-ahead distance in front of the tool is determinable;
- and
- a second probe means attached to the sensor body and directed toward a target region including the tip of the tool and the feature under the tip of the tool, for providing an image of the target region whereby the position of the tip of the tool is determinable.
Dependencies are inferred from the claim text.