Construction Machine Actuator Control for Latency Compensation

Solution Overview

Problem

Construction machines, such as remote-controlled demolition robots and excavators, face significant latency issues in actuator control, leading to reduced accuracy and increased risk of over-steering due to delays between control command input and actuator response.

Innovation Solution

A control device that transmits both the coordinate and its time derivatives to the actuator control unit, enabling prediction of future control commands and compensating for transmission delays, thereby reducing perceived latency and improving handling precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If real-time control commands are transmitted over a communications network, then the construction machine can be controlled remotely, but time delay occurs over the communications link reducing control accuracy

Engineering Contradiction:

Improveremote control capabilityVSAvoidcontrol latency

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The system performs preliminary action by predicting future control command coordinates before they are needed. The actuator control unit calculates predicted coordinates based on current coordinates and time derivatives, then uses these predictions to compensate for the known communication delay T, effectively preparing the control system in advance for the delayed commands that will arrive.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by using the known communication delay T as a parameter in the prediction calculation. The predicted coordinate x(t) is calculated using the current coordinate x(t-T) and its time derivatives, with the delay T serving as a feedback parameter that adjusts the prediction to compensate for the specific latency in the communication link.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If control commands are transmitted with delay, then the construction machine can operate over long distances, but the operator experiences reduced control accuracy and over-steering issues

Engineering Contradiction:

Improveremote operation rangeVSAvoidcontrol accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary action by predicting future control command coordinates before they are needed. The actuator control unit calculates predicted coordinates based on current coordinates and time derivatives, then uses these predictions to compensate for the known communication delay T, effectively preparing the control system in advance for the delayed commands that will arrive.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The predicted coordinate x(t) serves as an intermediary between the delayed actual coordinate x(t-T) and the actuator control. Instead of directly using the delayed coordinate, the system introduces a predicted coordinate that bridges the time gap, allowing the actuator to respond as if receiving real-time commands while maintaining the ability to operate over long distances with delayed communication.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If the control system uses current coordinates only, then the system is simple to implement, but the actuator response is delayed and causes over-steering

Engineering Contradiction:

Improvecontrol system simplicityVSAvoidhandling precision

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The system performs preliminary action by predicting future control command coordinates before they are needed. The actuator control unit calculates predicted coordinates based on current coordinates and time derivatives, then uses these predictions to compensate for the known communication delay T, effectively preparing the control system in advance for the delayed commands that will arrive.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system applies parameter changes by incorporating the time derivative v(t) of the coordinate in addition to the coordinate x(t) itself. This change in parameters allows the prediction function to estimate future coordinates, transforming the control approach from reactive (using only current values) to proactive (using current values to predict future needs).

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20240026645A1Construction machines with reduced latency actuator controls

Publication Date: 2024.01.25 HUSQVARNA AB

AI summary

A control device for controlling one or more actuators (110, 120, 130, 140) on a construction machine (100), the control device comprising a control input arrangement configured to receive a manual control command from an operator for controlling the one or more actuators, and to output a coordinate indicative of the manual control command as function of time, the control device further comprising a processing unit arranged to determine a first time derivative of the coordinate, and a transmitter arranged to transmit the coordinate and the first time derivative of the coordinate to an actuator control unit of the construction machine, thereby enabling compensation for time delay between the control device and the construction machine by the actuator control unit, wherein the time delay T to be compensated for is based on a pre-determined calibration setting.