Power assist device and method of controlling the power assist device

Abstract

A method of controlling a power assist device including a workpiece holding device, a handle, a force sensor that measures operating force of a worker that acts on the handle, a robot arm that supports the workpiece holding device, and a control device that controls an action of the robot arm based on a measurement result of the force sensor. The workpiece holding device includes an angle sensor that measures an inclination angle of the workpiece holding device. An action of robot arm is controlled by the control device based on measurement results of the angle sensor and of the force sensor.

Description

technical field [0001] The present invention relates to a power assist device, in particular to a power assist device and a method for controlling the power assist device. Background technique [0002] At production sites of industrial products and the like, assisting devices are used as devices that provide support for conveyance of heavy objects (workpieces) by operators. The operation of assembling the workpiece includes handling and positioning the workpiece. The operator and the assist device can cooperate to transfer the workpiece, and the assist device can bear the force required to transfer the workpiece. The operator can efficiently set the workpiece by teaching the positioning of the workpiece to the assisting device. In other words, the purpose of using the power assist device is to reduce the operator's labor and improve work efficiency. [0003] There is known a power assist device that includes a drive mechanism (such as a motor and an actuator) for each of ...

AI Technical Summary

Problems solved by technology

However, in the prior art, the inclination angle θ of the workpiece holding device 23 is not considered when obtaining the offset value

[0022] Therefore, the power assist device 21 sets an offset value (+Mg) to the operating force Fγ estimated based on the measured value Sγ of the force sensor 23d along the γ-axis direction in consideration of only the gravitational force Mg applied to the handle 23c, and thus cannot Accurately evaluate the operator's operating force (Fα, Fγ) while the windshield 30 is held by the workpiece holding device 23 when the windshield 30 is tilted at an angle θ

[0023] In addition, if the operator's operating force (Fα, Fγ) cannot be accurately evaluated, the assist amount required by the power assist device 21 calculated by the control device 25 cannot be successfully obtained.

This creates a situation in which the force (operation force) required to force the operator to operate becomes large and the operation direction required by the operator cannot correspond to the direction in which the windshield 30 is actually placed, thereby deteriorating the operability of the power assist device.

[0024] Therefore, in the case where the workpiece is conveyed in an inclined state, it is difficult for the prior art assisting device to convey the workpiece in the desired direction and perform accurate placement.

In addition, there is also the problem that it takes time to place the workpiece and the handling efficiency cannot be improved as expected

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