Mobility control system for series hybrid tracked vehicles

Abstract

The invention concerns a mobility control system used in series hybrid vehicles. The invention particularly relates to a system that improves the mobility and performance of tracked vehicles by precisely managing throttle, brake, and steering movements, enabling movement capabilities suited to difficult terrain with different driving modes and torque distribution; processes real‐time data via speed sensors and a closed‐loop controller to enhance vehicle stability and safety; and improves the driving experience by increasing the fast response ability of torque‐controlled electric motors, thereby responding instantly to driver commands.

Description

[0001] MOBILITY CONTROL SYSTEM FOR SERIES HYBRID TRACKED VEHICLES

[0002] TECHNICAL FIELD

[0003] The invention relates to a control system developed for the mobility control of series hybrid tracked vehicles.

[0004] Specifically, the invention pertains to a mobility control system that improves the offroad capabilities and performance of tracked vehicles; manages throttle, brake, and steering movements with high precision to enable movement under tough terrain conditions in different driving modes and torque distributions; increases vehicle stability and driving safety by processing real-time data using speed sensors and a closed-loop controller; and enhances the driving experience by employing torque-controlled electric motors that respond quickly to driver commands.

[0005] STATE OF THE ART

[0006] Today, due to the increasing consumption and nearing depletion of fossil fuels, along with their low efficiency, environmental damage, and high costs, alternative energy solutions are being sought. As a result of efforts to produce power units that are environmentally friendly, cost-efficient, and operate on alternative energy sources other than fossil fuels, hybrid powertrain technology has emerged. Developed to reduce fossil fuel consumption, enhance energy efficiency and deliver high performance, hybrid vehicles successfully lower carbon emissions.

[0007] Hybrid vehicles, possessing both electric motors and internal combustion engines, do not require external charging, offering convenience to users. These eco- and budgetfriendly vehicles are expected to spread increasingly among broader user bases. Vehicles with both electric and internal combustion engines are classified as hybrid vehicles. The primary goal in their production is to minimize fossil fuel consumption and enhance vehicle performance. In hybrid systems, electric motors are used in addition to internal combustion engines based on power demand and efficiency considerations. For example, when the internal combustion engine operates at low efficiency, the electric motor supplements the required output, ensuring efficient power delivery and fuel savings. When the electric motor depletes its stored energy, the internal combustion engine recharges it while driving, enabling extended range operation without external charging.

[0008] In current technology, motion control for tracked vehicles is traditionally achieved using hydraulic units integrated within the transmission. These systems operate by engaging the hydraulic mechanism upon a turning request, slowing the inner track and accelerating the outer track via a gear mechanism, thus enabling safe and stable steering. However, the complexity of transmission components poses procurement challenges, and hydraulic systems bring about additional issues in terms of maintenance and durability. These systems, requiring high maintenance and being complex, may prevent operational continuity. Moreover, such hydraulic systems often operate at low efficiency, leading to significant energy losses.

[0009] In hybrid electric tracked vehicles, existing mobility control systems typically rely on speed-controlled motor systems. These systems adjust the average speeds of each track based on throttle input and steer the vehicle by adjusting the speed difference between right and left tracks based on steering input. This speed-based control has limitations in delivering sudden acceleration demands and may suffer from sensitivity loss during dynamic maneuvers, causing instability and reduced handling precision. Synchronizing the speeds of both tracks is also challenging, potentially leading to balance and stabilization issues. Furthermore, since motor current is not directly proportional to motor speed, complex nonlinear mappings are required between current limitations and driver demand in such systems. Consequently, the challenges outlined above necessitate the development of a new mobility control system.

[0010] OBJECTIVE OF THE INVENTION

[0011] The present invention pertains to a mobility control system developed for the mobility management of series hybrid tracked vehicles and aims to eliminate the aforementioned disadvantages while providing new technical advantages.

[0012] A key objective of the invention is to offer an effective solution to issues encountered during the production and procurement of conventional transmissions, and to the maintenance and durability issues of hydraulic systems. These systems reduce complexity, improve manufacturing efficiency, and lower operational and service costs. Additionally, the ability of hybrid systems to recover energy during braking significantly improves overall system efficiency. The recovered energy is stored in batteries for later use, optimizing energy consumption and offering a cost-effective, sustainable alternative. Improved energy efficiency reduces operational costs and minimizes environmental impact through lower carbon emissions.

[0013] Another objective is to employ a torque-control approach that allows more precise and effective driver response in tracked vehicles. These torque-controlled systems enhance sensitivity during sudden or dynamic maneuvers, preventing instability. The invention establishes a direct and effective correlation between the driver's throttle input and vehicle acceleration, ensuring natural and reliable interaction between vehicle and driver. Furthermore, because torque is directly proportional to electric current, driver demands can be implemented directly through current limitation without affecting driving stability. The closed-loop control system designed to maintain constant speed differences during turns ensures adaptation to various path and terrain conditions, achieving the desired turning behavior. These integrated systems offer advanced engineering solutions that enhance vehicle performance and driving safety, thereby optimizing modern tracked vehicle operational efficiency and improving user experience. The structural and characteristic properties, along with all advantages of the invention, will be more clearly understood from the following detailed description, which should be considered during evaluation.

[0014] DETAILED DESCRIPTION OF THE INVENTION

[0015] This detailed description explains preferred configurations of the mobility control system solely for better understanding, without creating any limiting effect.

[0016] Tracked vehicles are frequently used in sectors such as automotive, defense, and construction due to their off-road capabilities and are operated under challenging conditions. With increasing interest in hybrid electric drive systems, electrification and powertrain management have emerged as significant innovations for tracked vehicles as well. In this context, our invention focuses on a mobility control system for series hybrid tracked vehicles. A configuration with two drive systems mechanically independent of each other and directly connected to right and left tracks is used, and maneuverability and mobility are ensured through the developed control system.

[0017] Today, the driver performs desired maneuvers using throttle, brake, and steering inputs. The mobility control system collects these inputs via sensors, performs necessary calculations, and transmits the commands as torque requests to electric motors connected directly to the tracks, while also retrieving relevant data from speed sensors. As a result, the driver can effectively control both vehicle acceleration and movement. In our invention, throttle, brake, and steering movements are measured using analog sensors and transmitted to the mobility control system via the CAN BUS communication system. The sensor data is then processed through calibration routines and converted into percentage values. These percentage signals are sent to the mobility command shaping block. Driver input signals in percentage form are processed by specific shaping subsystems to meet various demands.

[0018] Mobility Control System

[0019] The throttle signal is passed through a subsystem called the traction shaper in the mobility command shaper. This module determines the required traction torque based on throttle position and the selected driving mode. As shown below, the traction shaper includes three different modes:

[0020] First, the smooth throttle response mode is designed for calm and controlled driving conditions. The balanced throttle response mode provides a linear relationship between the vehicle's acceleration and the throttle input, maintaining a consistent response rate. Lastly, the aggressive throttle response mode allows sharp and dynamic driving by adjusting the throttle response accordingly. In all three modes, if the brake is engaged, the traction torque is immediately set to zero. These modes are intended to ensure optimal performance under various driving conditions.

[0021] Traction Shaper The steering signal is processed by a steering shaper module in the mobility command shaper, taking the current vehicle speed into account. This module analyzes the driver's steering input and the current speed of the vehicle to determine the required speed difference between the right and left tracks for executing the maneuver with appropriate accuracy. Specific curves developed for the vehicle are used to determine the required speed differential. An example curve is provided below for the electrified tracked vehicle under development. The curve is created by gathering driving and powertrain performance data from the conventional version of the vehicle and adjusting it accordingly. This component— the steering shaper, being a key element in maneuverability— ensures stable and safe vehicle steering through precise control.

[0022] Steering Shaper

[0023] As illustrated in the figures above, the closed-loop controller in our invention responds to the difference between the requested and measured speed differences. A PI (Proportional + Integral) control method is employed, where both the error and its integral contribute a gain-scaled amount of steering torque. As the error increases or remains constant, the steering torque increases accordingly. This steering torque is subtracted from the inner track's drive torque and added to the outer track's drive torque, thus increasing the torque differential between the two tracks until the desired speed differential is achieved. Once the system stabilizes and the error becomes zero, the steering torque is fixed, allowing accurate vehicle maneuvering. The closed-loop controller continuously monitors this speed error and manages torque distribution to ensure stable and precise steering.

[0024] The speed sensors in the invention measure the instantaneous speeds of the electric motors mounted on the inner and outer tracks and transmit this data to the closed-loop controller. These speed readings are essential for calculating speed errors and performing corrective torque adjustments. They also play a key role in calculating vehicle velocity.

[0025] The electric motors in the invention, fulfilling the drive function, receive torque commands and convert electrical energy into mechanical energy. In addition to supplying the requested torque, they enable the vehicle to accelerate and maneuver. Their precise control and high efficiency offer superior mobility across various driving conditions.

[0026] Thanks to the rapid response capability of electric motors, driver commands are executed immediately, facilitating smooth acceleration and steering. By distributing torque across inner and outer tracks, these motors maintain balance and promote high maneuverability.

[0027] In conclusion, the developed mobility control system significantly enhances the off-road capability and performance of tracked vehicles. Precisely managing throttle, brake, and steering movements, the system ensures mobility under tough terrain using driving modes and torque distribution. Real-time data processing through speed sensors and closed-loop control increases vehicle stability and safety. Torque-controlled electric motors with fast response enrich the driving experience by instantly responding to driver inputs. This innovative approach allows for more efficient use of tracked vehicles across multiple industries and establishes a promising foundation for future applications.

[0028] The scope of protection for this application is defined in the claims section and shall not be limited by the exemplary embodiments described herein. It is evident that a person skilled in the art can make use of similar architectures or apply its principles to other fields serving analogous purposes. Therefore, such variations shall clearly fall short of novelty or inventive step under the state-of-the-art criteria.

Claims

CLAIMS1. A system developed for mobility control of hybrid tracked vehicles, characterized in that it comprises: a mobility control system that enhances the mobility and performance of tracked vehicles by precisely managing throttle, brake, and steering movements; enabling movement under challenging terrain using driving modes and torque distribution; processing real-time data through speed sensors and a closed-loop controller to improve vehicle stability and driving safety; and employing torque-controlled electric motors to increase rapid response capability, instantly responding to driver input and improving the driving experience.

2. The mobility command shaper as claimed in Claim 1, characterized in that it comprises: a traction shaper that determines the required traction torque based on throttle position; and / or a steering shaper that analyzes the driver's steering actions and current vehicle speed to determine the appropriate speed differential between the right and left tracks, ensuring stable and safe steering based on the current vehicle velocity and requested steering angle.

3. The traction shaper as claimed in Claim 2, characterized in that it includes: a controlled throttle response mode designed for smoother control; a balanced throttle response mode where total torque applied to the tracks by motors is linearly related to throttle input, providing balanced response speed; and a performance-oriented aggressive throttle response mode configured for dynamic and sharp vehicle movements.

4. The mobility control system as claimed in Claim 1, characterized in that it comprises: a closed-loop controller that measures the difference between requested and actual speed differentials and computes corrections using PI (Proportional + Integral) control, wherein the error term and its integral are scaled to generate steering torque used to manage vehicle direction.

5. The mobility control system as claimed in Claim 1, characterized in that it comprises: speed sensors mounted on inner and outer tracks that measure the instantaneous speeds of the electric motors and transmit this data to the closed- loop controller.

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