Horizontal Articulated Robot Shaft Vibration Control
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Solution Overview
Problem
Horizontal articulated robots experience significant vibration in vertical directions due to shaft deformation, leading to decreased work capacity and quality, as existing control systems fail to effectively dampen these vibrations in a timely manner.
Innovation Solution
A control apparatus that incorporates an inertial sensor to detect angular velocity and feeds back this information to the motor control system, using filtering processes such as lowpass and band elimination filters to reduce vibration by adjusting current commands and velocity commands, thereby directly controlling the reaction forces acting on the shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If natural damping is used to reduce shaft vibration, then vibration is eventually suppressed, but work capacity decreases due to waiting time and work quality degrades due to vibration during operation
Solution Approach 1:
The patent applies feedback control by detecting shaft vibration using an inertial sensor and feeding back the detected information to the motor control system. The control section adjusts the current command based on the detected vibration, creating a closed-loop control system that actively suppresses vibration in real-time rather than relying on passive natural damping.
Solution Approach 2:
The patent replaces the mechanical/passive damping approach with an electronic control system. Instead of relying on mechanical damping elements or natural structural damping, the system uses electronic sensors and controllers to detect and counteract vibration through adjusted motor commands, substituting mechanical solutions with electronic control.
2Object-affected harmful factors
If inertial sensor output is fed back to motor control, then vibration suppression performance improves, but risk of position shifts and loss of low-frequency information increases
Solution Approach 1:
The patent changes the parameters of the feedback signal by applying filtering operations. A lowpass filter removes high-frequency noise while preserving low-frequency position information, and a band elimination filter removes specific vibration frequency components. This parameter transformation allows vibration suppression without compromising position accuracy.
Solution Approach 2:
The patent introduces filtering operations as intermediary processing steps between the inertial sensor and the motor control. These filters act as mediators that selectively process the sensor signal, removing harmful vibration components while preserving useful position information, thus protecting against position shifts.
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 significantly reduces shaft vibration in vertical directions, enhancing work capacity and quality by improving response speed and vibration suppression performance while preventing position shifts and maintaining low-frequency information integrity.
Implementation Method 1
an inertial sensor provided in the second arm
Implementation Method 2
a control section that feeds back output of the inertial sensor to control of the motor and drives the motor
Implementation Method 3
reduction of vibration in axial directions of the shaft
Data Source
AI summary
A control apparatus controls a horizontal articulated robot including a base, a first arm provided at the base and pivoting around a first axis relative to the base, a second arm provided at the first arm and pivoting around a second axis relative to the first arm, a shaft provided in the second arm and linearly moving in directions along a third axis, a motor that drives linear motion of the shaft, a position detector that detects a position of the motor, and an inertial sensor provided in the second arm, and includes a control section that feeds back output of the inertial sensor to control of the motor and drives the motor.