US 6,218,801 B1Granted

Method for supervision of the movement control of a manipulator

AssigneeABB AB

InventorsTorgny Brogårdh, Staffan Elfving, Ingvar Jonsson, Stig Moberg, Fredrik Skantze

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Abstract

A method for supervision of the movement control of a manipulator. The manipulator comprises at least one movement axis, a servo (9) for controlling the axis in accordance with supplied reference values for position, speed and acceleration (ψref, {dot over (ψ)}ref, {umlaut over (ψ)}ref). A plurality of dynamic parameters (dyn-par) are calculated in dependence on reference values for the position and speed of the axis and a dynamic model (7) which describes the static and dynamic properties of the robot. A torque signal (τmr) is generated by the servo in dependence on the control error torque (τerr) of the servo. An alarm value (LV) is calculated as a function of the current acceleration ({umlaut over (ψ)}m), at least any of the dynamic parameters and one or more of the following signals: the control error torque (τerr) of the servo, the reference value for the acceleration ({umlaut over (ψ)}ref) and the torque signal from the servo (τmr), and while using one or more signal filters. An alarm limit (LG) is calculated as a function of one or more of the following parameters: a constant, the current position (ψm), the current speed ({dot over (ψ)}m), the current acceleration ({umlaut over (ψ)}m) any of the dynamic parameters, the control error torque (τerr) of the servo, the reference value for the acceleration ({umlaut over (ψ)}ref) and the torque signal from the servo (τmr). The alarm value is compared with the alarm limit and an alarm signal (ALARM) is generated in dependence on the comparison.

A method for supervision of the movement control of a manipulator, the manipulator comprising a movable part which may be moved relative to a fixed part or another movable part, at least one movement axis (A1-A6) for positioning the movable part, a motor which drives the shaft and hence the movable part, a servo (9) for controlling the axis in accordance with supplied reference values for position, speed and acceleration (ψref,{dot over (ψ)}ref,{umlaut over (ψ)}ref), and a position sensor (10) adapted to supply an output signal which defines the current position (ψm) of the axis, wherein

a plurality of dynamic parameters (J*tot,J*totMAX,k*Tdev,τ*devm,τ*distin,τ*deva) are calculated in dependence on reference values for the position and speed of the axis and a dynamic model (7) which describes the static and dynamic properties of the robot,
the current acceleration ({umlaut over (ψ)}m) of the axis is calculated on the basis of the current position (ψm) of the axis,
a torque signal (τmr) is generated by the servo in dependence on the control error torque (τerr) of the servo, characterized in that it further comprises the following steps:
an alarm value (LV) is calculated as a function of the current acceleration ({umlaut over (ψ)}m), at least some of the dynamic parameters (J*a,J*m,c*,k*) and one or more of the following signals:
the control error torque (τerr) of the servo, the reference value for the acceleration ({umlaut over (ψ)}ref) and the torque signal from the servo (τmr), and while using one or more signal filters (G*1,G*2,G2−1*),
an alarm limit (LG) is calculated as a function of one or more of the following parameter:
a constant, the current position (ψm), the current speed ({dot over (ψ)}m), the current acceleration ({umlaut over (ψ)}m), any of the dynamic parameters (J*tot max ,J*deva,k*dev,τ*dist,τ*dev), the control error torque (τerr) of the servo, the reference value for the acceleration ({umlaut over (ψ)}ref) and the torque signal from the servo (τmr),
the alarm value is compared with the alarm limit and an alarm signal (LARM) is generated in dependence on the comparison.

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Abstract

Claims15