Robot Joint Drive Encoder Integration on Motor Circuit Board
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional robot joint drives face challenges in achieving precise and safe positioning, particularly in humanoid robots, due to complex structures and increased demands in industrial automation, requiring simpler and more reliable designs for accurate movement and reduced interference.
Innovation Solution
A robot joint drive design featuring a magnetic field encoder or inductive encoder at the free end of the output shaft, integrated with a commutation sensor system on a common motor circuit board, allowing for precise, contact-free position determination without additional connections, using a magnet or induction scale to detect the rotational position with high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional encoder mounting structure is used with separate connections, then the encoder can be mounted on the output shaft, but the device complexity and installation space increase
Solution Approach 1:
The encoder is integrated directly into the motor circuit board, merging the encoder function with the existing control electronics. This eliminates separate encoder connections and mounting structures, reducing device complexity while maintaining position determination accuracy through direct integration of the encoder sensor array and evaluation electronics on the same circuit board.
Solution Approach 2:
The motor circuit board serves multiple functions: it acts as both the control electronics carrier and the encoder mounting platform. The circuit board's ground plane and structural elements are utilized as part of the encoder system, allowing the same component to fulfill both electrical control and positional sensing functions simultaneously.
2Measurement precision
If additional encoder connections are added to the motor circuit board, then the encoder can be connected, but the device complexity and manufacturing costs increase
Solution Approach 1:
The encoder connections are merged with the existing motor circuit board traces and power supply lines. The encoder receives power and transmits signals through the same circuit board infrastructure already present for motor control, eliminating the need for additional external connections and simplifying the manufacturing process.
Solution Approach 2:
The motor circuit board's existing ground plane and electrical infrastructure serve the encoder automatically without requiring separate connection pathways. The circuit board's structural elements and electrical layers provide both mechanical support and electrical connectivity for the encoder, making the system self-sufficient.
3Measurement precision
If the encoder is positioned closer to the output shaft free end, then the position determination accuracy improves, but the risk of interference from metal parts increases
Solution Approach 1:
The motor circuit board acts as an intermediary between the encoder and the metal components of the motor. The circuit board's ground plane and non-magnetic structure provide electrical connectivity and mechanical support while shielding the encoder from magnetic field interference generated by nearby metal parts.
Solution Approach 2:
The encoder is extracted from traditional mounting locations near metal components and repositioned on the motor circuit board, which provides a non-magnetic environment. This separation removes the encoder from the harmful magnetic field zones while maintaining close proximity to the output shaft for accurate position detection.
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 design enables precise position determination of less than 0.1°, reduces installation space, and simplifies the drive sensor system, enhancing the reliability and safety of robot joint operations while minimizing manufacturing costs and interference.
Implementation Method 1
the transmitter element can be a magnet and the encoder can be a magnetic field encoder, with the magnetic field encoder determining the rotational position of the output shaft by means of the magnetic field of the magnet at the free end of the output shaft
Implementation Method 2
the transmitter element can be an induction-changing scale and the encoder can be an inductive encoder, with the inductive encoder determining the rotational position of the output shaft by means of the changing inductance through the scale at the free end of the output shaft
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a robot joint drive (1) comprising a stationary housing (2), an output part (5) rotatable relative to the stationary housing, an electric drive motor (9), and a gearbox (16), wherein a drive shaft (17) of the electric drive motor (9) is coupled via the gearbox (16) to an output shaft (27) of the rotatable output part (5) in order to rotate the output part relative to the stationary housing (2). According to the invention, a sensor element is arranged at a free end of the output shaft (27), which extends from the output part (5) into the gearbox (16), and an encoder is provided, wherein the encoder determines the rotational position of the output shaft (27) by means of the sensor element.