Multi-Sensor Robot Arm Force Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional robot systems face challenges in precisely controlling forces across a wide range, from fine external forces to large external forces, due to limitations in sensor detectable ranges and interference from friction and inertia, leading to inaccurate force sensing and control.
Innovation Solution
A robot apparatus equipped with a multi-joint robot arm featuring a combination of sensors with different detectable ranges, where a controlling unit selectively uses the sensing results from these sensors to achieve high-precision force control across a wide range of forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a sensor with a large detectable range is used, then the robot can sense large external forces, but the sensing precision for fine external forces deteriorates due to noise
Solution Approach 1:
The patent divides the force sensing function into multiple segments by using several sensors with different detectable ranges. Each sensor is responsible for a specific force range, and the controlling unit selects the appropriate sensor based on the current force magnitude. This segmentation allows the system to achieve both wide detectable range and high precision for fine forces.
Solution Approach 2:
The patent changes the parameter of sensor detectable range by employing multiple sensors with different range specifications. The controlling unit dynamically selects which sensor to use based on the external force magnitude, effectively adapting the sensing parameter to match the current operational requirements.
2Measurement precision
If a sensor with a small detectable range is used, then the sensing precision for fine external forces is improved, but the robot cannot sense large external forces
Solution Approach 1:
The patent creates a universal force sensing capability by combining multiple sensors with different detectable ranges. The system can handle both fine and large external forces by selecting the appropriate sensor, making the robot applicable to diverse assembly tasks ranging from flexible cable assembly to rigid metal part assembly.
Solution Approach 2:
The patent introduces dynamic sensor selection where the controlling unit automatically chooses the most appropriate sensor based on the current external force magnitude. This dynamic adaptation allows the system to maintain optimal sensing precision across varying force conditions.
3Adaptability or versatility
If torque sensors are arranged in each joint of the robot arm, then the robot can sense external forces anywhere on the robot, but the sensing precision deteriorates due to friction and inertia losses
Solution Approach 1:
The patent extracts the force sensing function from the joint torque sensors and places it directly at the end-effector. This extraction eliminates the interference from friction and inertia in the driving portions, providing clean and precise force sensing data for control.
4Measurement precision
If force sensors are arranged in the end portion of the robot arm, then the sensing precision for fine external forces is improved, but the robot cannot sense forces acting on other parts of the robot arm
Solution Approach 1:
The patent uses the robot arm's transmission mechanism as an intermediary to transfer forces acting on any part of the robot arm to the end-effector force sensors. This allows the sensors positioned at the end portion to detect forces acting elsewhere on the robot structure while maintaining high sensing precision.
Data Source
AI summary
An object of the present invention is to sense forces from a fine external force to a large external force with high precision, and enable high-precision control. A multi-joint robot arm has a first sensor arranged in an end portion, and second sensors arranged in joints, respectively. The first sensor and the second sensor have different detectable ranges from each other for a detectable force. A controlling apparatus selects which sensing result of a sensor should be used between sensing results of the first sensor 131 and the second sensor, and controls a robot arm by using the selected sensing result of the sensor.