Load-Adaptive Tractor Speed Control on Variable Ground

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Solution Overview

Problem

Tractors used in intralogistics often lack the ability to determine the complete load and ground profile, leading to unsafe driving speeds and inefficient transport due to drivers' lack of knowledge and information, resulting in accidents and reduced productivity.

Innovation Solution

A tractor equipped with a load determination device, ground profile determination device, and control device to limit speed based on load and ground conditions, using sensors and visual and acoustic signals to ensure safe and efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the driver manually determines driving speed based on load and ground conditions, then operational flexibility is maintained, but safety is compromised due to lack of complete information and driver expertise

Engineering Contradiction:
Improvedriving safetyVSAvoidspeed control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The tractor system automatically determines its own load and ground profile, then autonomously calculates and enforces the maximum permissible speed without requiring external expert intervention. The control device uses sensor data from the tractor's own systems (motor currents, inclination sensors) to self-regulate speed, making the system self-sufficient for safety-critical decisions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system continuously monitors load conditions through motor current measurements and ground profile through inclination sensors, feeds this information back to the control device, which then adjusts the maximum permissible speed accordingly. This closed-loop feedback ensures speed limitations are dynamically adapted to actual operating conditions.

Inventive Principle:
Principle #23Feedback

2Productivity

If the driver selects higher speeds to improve transport efficiency, then productivity increases, but the risk of accidents increases due to insufficient information about load and ground conditions

Engineering Contradiction:
Improvetransport efficiencyVSAvoidaccident risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system determines the maximum permissible speed in advance based on the current load and ground profile before the tractor begins moving or changes speed. This preliminary determination ensures that speed limits are established before hazardous conditions arise, preventing accidents while allowing optimal speeds to be maintained for productivity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically changes the speed parameter based on varying load and ground conditions. By continuously adjusting the maximum permissible speed parameter according to actual operating conditions, the system maintains high productivity when conditions allow while automatically reducing speed when safety concerns arise.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If advanced driver training is provided to improve speed selection, then safety can be enhanced, but operational costs and time investment increase

Engineering Contradiction:
Improvespeed selection accuracyVSAvoiddriver training time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the human driver's cognitive system (training, knowledge, judgment) with an automated electronic control system that objectively measures load and ground conditions. This substitution eliminates the need for extensive driver training while achieving more consistent and accurate speed selection based on actual physical measurements rather than human expertise.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If the tractor is equipped with comprehensive sensors to determine load and ground profile, then safety is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecondition determination accuracyVSAvoidsensor system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses multi-functional sensing approaches where existing tractor components serve multiple purposes. For example, motor current measurements originally for drive control are also used for load determination, and inclination sensors originally for stability control are also used for ground profile determination. This universality reduces the need for dedicated separate sensors.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control device acts as an intermediary that processes information from existing sensors and existing drive system measurements to derive load and ground profile data. Rather than requiring direct specialized sensors for each parameter, the control device mediates between available sensor data and the required information, using calculations and algorithms to extract the needed parameters.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3689698B2Tower
Publication Date: 2026.03.25 STILL GMBH
  • EP3689698B2 patent drawingFigure 1
  • EP3689698B2 patent drawingFigure 2
  • EP3689698B2 patent drawingFigure 3

AI summary

The invention relates to a tractor (1, 21) with a loading platform and/or a trailer hitch (12) for at least one trailer. The objective of providing a means of controlling the driving speed of a tractor depending on the load and/or ground profile is achieved according to the invention by equipping the tractor (1, 21) with a control device for limiting the driving speed of the tractor (1, 21), a load detection device (13), and/or a ground profile detection device (10, 11).24) wherein the load detection device (13) is configured to determine the weight of a load and transmit this information to the control device, the ground profile detection device (10, 11) is configured to determine a current ground profile and transmit this information to the control device, and the control device is configured to limit the driving speed of the tractor (1, 21) to a maximum permissible driving speed depending on a load determined by the load detection device (13) and/or a ground profile determined by the ground profile detection device (10, 11; 24).