Distributed Torque Sensors in Robot Arm Links
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Solution Overview
Problem
The integration of a torque sensor in a robot arm's joint increases the weight and complexity of the joint, necessitating the use of expensive high-rigidity parts and complicating the structure, which is undesirable for collaborative robots that need to detect contact with people or objects safely.
Innovation Solution
A robot arm mechanism with a rotational joint and a link equipped with multiple torque sensors distributed along the link, rather than within the joint, allowing for simplified joint design, reduced weight, and improved contact detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a torque sensor is equipped in the joint on the tip side of the robot, then contact detection capability is improved, but the weight of the tip portion increases and the weight load on the base side increases
Solution Approach 1:
The link is divided into multiple link portions (first link portion, second link portion, third link portion) with torque sensors distributed at different positions. This segmentation allows the system to detect contact forces more effectively while distributing the weight load across multiple lighter components rather than concentrating a heavy sensor in one joint.
2Measurement precision
If a torque sensor is equipped in the joint, then contact detection capability is improved, but the structure inside the joint becomes more complex and larger
Solution Approach 1:
Instead of placing one complex torque sensor in each joint, the invention segments the detection function across multiple simpler torque sensors distributed along the link. Each sensor has a simpler structure, and together they provide comprehensive contact detection capability, reducing the complexity within any single joint.
Solution Approach 2:
The torque sensors are arranged in a distributed pattern along the length of the link rather than being concentrated in the joint space. This spatial redistribution across different dimensions (along the link length) reduces the complexity density within any single joint while maintaining overall detection capability.
3Strength
If high-rigidity parts with high weight are used to cope with increased weight, then structural strength is improved, but cost increases
Solution Approach 1:
By segmenting the link into multiple portions with distributed torque sensors, the overall weight increase is minimized compared to using a single heavy sensor. This allows the use of lighter, lower-cost materials while maintaining sufficient structural strength through the distributed sensor configuration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the weight and cost of the joint, enhances sealing performance, and increases the sensitivity of contact detection, enabling safer and more efficient operation of collaborative robots by distributing torque sensors along the link between rotational joints.
Implementation Method 1
The link includes a plurality of link portions. The link portions are coupled to each other via torque sensors.
Data Source
AI summary
An object of the present invention is to simplify a joint, such as reducing the weight of the joint, in a robot arm mechanism capable of detecting contact of a person or an object. A robot arm mechanism (1) according to an embodiment of the present disclosure includes rotational joints (J1, J2). The rotational joint (J1) and the rotational joint (J2) are connected to each other by a link (30). The link (30) includes a plurality of link portions (31, 33, 35, 37). The link portions (31, 33) are coupled to each other via a torque sensor (61), the link portions (33, 35) are coupled to each other via a torque sensor (63), and the link portions (35, 37) are coupled to each other via a torque sensor (65).