Virtual Force Sensing for Robot Surface Alignment Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In surface alignment tasks, the detection of force and moment by a force sensor for a robot is challenging due to the correlation between the control point and the sensor position, leading to inaccurate alignment or prolonged alignment times.
Innovation Solution
A control apparatus using a virtual sensor associated with a physical force sensor, projected on a control plane, to accurately detect moments and forces for precise surface alignment, adjusting the gripper's movement based on geometric conditions and detection results from the virtual sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a force sensor is used to detect force and moment for surface alignment, then alignment can be achieved, but detection accuracy deteriorates due to correlation between control point position and sensor position
Solution Approach 1:
The patent introduces a virtual sensor as an intermediary element that mediates between the physical force sensor and the control system. The virtual sensor is positioned at the control point rather than at the physical sensor location, eliminating the need to account for position correlation. It calculates and provides force and moment values that are directly applicable to the control point, serving as a bridge that simplifies the control architecture while maintaining measurement accuracy.
Solution Approach 2:
The patent creates a virtual copy of the force sensor at the control point position. This virtual sensor replicates the sensing function without the physical constraints of the actual sensor's location. By copying the sensor's detection capability to the control point through calculation and transformation, the system achieves accurate force and moment detection at the desired location without moving the physical sensor.
2Manufacturing precision
If the gripper is rotated based on force and moment detection for surface alignment, then alignment between objects is achieved, but alignment time increases when detection is inaccurate
Solution Approach 1:
The patent implements a feedback control mechanism where the virtual sensor continuously provides accurate force and moment information to the control system. The controller uses this feedback to adjust the gripper's rotation in real-time, enabling precise surface alignment. The accurate feedback from the virtual sensor allows the system to make timely and accurate adjustments, reducing the time required to achieve proper alignment while maintaining high precision.
Data Source
Figure 1~2
Figure 3
Figure 4Aa~4Ad
AI summary
A technique allows a robot gripping one of two objects to perform appropriate surface alignment between the two objects. A control apparatus for a robot includes a virtual sensor associated with a force sensor and set on a control plane for predetermined control to control a position of a first object relative to a second object by causing a first surface of the first object gripped by a gripper to abut on a second surface of the second object, and a controller that performs the predetermined control based on a detection result from the virtual sensor using a control point set on the control plane based on a state of the first object being gripped by the gripper. The virtual sensor is projected on an imaginary line at a projection position between a predetermined contact point and the control point in an extending direction of the imaginary line on the control plane connecting the control point and the predetermined contact point being a contact point between the two objects and set on the control plane to place the first object into contact with the second object before the first surface abuts on the second surface in the predetermined control.