Robot Arm Feedback Control for Spline Shaft Vibration
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Solution Overview
Problem
Existing horizontal articulated robots, such as SCARA robots, fail to effectively suppress vibrations around the longitudinal axis of the second arm, leading to instability during operations like grasping and handling of objects.
Innovation Solution
A control device that includes an angular velocity sensor detecting angular velocity around an axis orthogonal to the pivot axis and parallel to the plane containing the pivot axis and the shaft, enabling feedback control to suppress vibrations in the spline shaft, thereby maintaining the position of the control point constant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If feedback control is implemented using an angular velocity sensor to suppress vibration in the horizontal direction, then the stability of the robot arm in the horizontal direction is improved, but vibration around the longitudinal axis (roll direction) of the second arm is not suppressed
Solution Approach 1:
The patent extends the vibration suppression control from a single horizontal direction to multiple dimensions by adding detection of angular velocity around the longitudinal axis (roll direction). The control device now processes angular velocity components in both the horizontal direction and the roll direction, enabling three-dimensional vibration suppression control that addresses vibrations in all relevant directions simultaneously.
2Measurement precision
If an angular velocity sensor is installed within the second arm to measure angular velocity, then the control precision for suppressing second arm vibration is improved, but the sensor cannot detect vibration around the axis along the longitudinal direction of the second arm
Solution Approach 1:
The patent makes the angular velocity sensor system universal by configuring it to detect angular velocity around multiple axes simultaneously - both the horizontal direction and the longitudinal axis (roll direction). This multi-functional sensor configuration allows a single sensor system to perform multiple detection functions, capturing all relevant vibration components for comprehensive control.
3Device complexity
If the control device only suppresses vibration in the horizontal direction, then the control algorithm is simple, but the robot exhibits instability during grasping and handling operations due to uncontrolled roll direction vibrations
Solution Approach 1:
The patent implements feedback control by continuously measuring angular velocity around both the horizontal direction and the longitudinal axis, then using this feedback information to adjust the drive section's operation. The control device processes the measured angular velocity components and generates corrective control signals that are fed back to the drive section, creating a closed-loop control system that actively suppresses vibrations in multiple directions simultaneously.
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
The solution effectively reduces vibrations in the spline shaft, ensuring stable grasping and handling of objects by maintaining the control point's position, enhancing the robot's operational stability and precision.
Implementation Method 1
an angular velocity sensor that is provided in the robot arm and that detects angular velocity around an axis orthogonal to an axial direction of the pivot axis
Data Source
AI summary
A control device controlling a robot including a robot arm, a drive section causing the robot arm to pivot around a pivot axis, a shaft that is provided at a position of the robot arm different from the pivot axis and that moves parallel to the pivot axis, and an angular velocity sensor that is provided in the robot arm and that detects angular velocity around an axis orthogonal to an axial direction of the pivot axis and parallel to a plane including the pivot axis and an axis of the shaft, the control device includes a processor that is configured to control the robot, wherein the processor is configured to perform feedback control on the drive section based on the angular velocity.