隨著車輛動態系統與電控技術之發展，如何在複雜路況與負載變動條件下，兼顧車輛穩定性及降低異常輪速偏差情形，已成為車輛控制系統設計中的重要課題。傳統被動式差速器的控制方式在面對路面摩擦力快速變化時，往往難以即時調整控制輸出，進而影響系統整體性能。本論文針對上述問題，建立一套以系統模型為基礎之控制策略設計方法，透過動態模型分析與狀態估測技術，發展一套可因應外在擾動與系統不確定性之控制架構。首先，建立受控系統之數學模型，並分析其動態特性，作為後續控制器與估測器設計之基礎。接著，設計一控制策略以實現輸入分配與系統穩定控制，為驗證所提出控制策略之可行性與有效性，本研究透過模擬環境進行多種操作情境測試，並比較不同控制條件下之系統表現。實驗結果顯示，所提出之控制策略能有效抑制系統之異常輪速偏差，使輪速收斂在車輛能穩定前行範圍內，在面對負載變化與擾動時，仍能維持良好之控制性能。綜合研究結果，本論文所提出之控制策略具備實際應用潛力，並可作為未來進一步整合高階控制方法或實體系統驗證之基礎。

A conventional open differential allows the left and right drive wheels to rotate at different speeds during cornering. However, because the torque transmitted to both wheels is constrained by the wheel with the lower available adhesion, excessive wheel slip may occur when either wheel travels over an icy or otherwise low-adhesion surface. Under such asymmetric road conditions, the low-adhesion wheel may rotate excessively, while the wheel on the higher-adhesion surface cannot fully utilize its available traction. Consequently, the effective driving force and wheel-speed stability of the vehicle are reduced.

This study investigates a dual-input active differential equipped with an additional assist gear and an independently controlled assist motor. The additional actuation input transforms the differential from a passive single-input mechanism into an actively controllable dual-input system. The main motor provides the primary driving torque, while the assist motor modifies the motion of the planetary gear and adjusts the torque distribution between the left and right drive wheels. Dynamic models of the conventional open differential and the proposed dual-input differential were established to analyze their speed relationships, torque transmission characteristics, controllability, and observability.

Based on the mechanical characteristics of the dual-input differential, a vehicle traction control strategy integrating Maximum Transmittable Torque Estimation (MTTE), road-load observers, and planetary-gear-speed-based slip detection was developed. The MTTE mechanism limits the main motor torque according to the estimated load capacity of the left wheel. The assist motor regulates the right-wheel torque and compensates for the driving torque required by the wheel on the higher-adhesion surface. To distinguish abnormal wheel slip from the wheel-speed difference naturally generated during cornering, Ackermann steering geometry was used to calculate the theoretical left- and right-wheel speeds under normal driving conditions. These theoretical wheel speeds were further converted into a reference planetary gear speed and compared with the planetary gear speed estimated from the measured differential states.

The proposed strategy was verified using a Hardware-in-the-Loop (HIL) platform integrating CarSim vehicle dynamics simulation, physical servo motors, a dual-input differential test rig, and a CompactRIO real-time controller. Six asymmetric low-adhesion scenarios were examined, including straight driving, left cornering, and right cornering, with either the left or right wheel traveling over an icy surface. Controlled and uncontrolled cases were compared using motor torque, wheel-speed responses, instantaneous slip ratios, and average absolute slip ratios. An ISO 3888-2 double-lane-change test with localized low-adhesion surfaces was also conducted at an initial vehicle speed of 70 km/h.

The experimental results show that the proposed strategy reduced the average absolute slip ratio of the low-adhesion wheel in all six test scenarios. For straight driving with left- and right-side low-adhesion surfaces, the average absolute slip ratios decreased from 12.6% to 0.50% and from 8.7% to 0.57%, respectively. During left cornering, the corresponding values decreased from 11.2% to 0.90% for the left-side low-adhesion case and from 27.9% to 0.78% for the right-side low-adhesion case. During right cornering, the average absolute slip ratio decreased from 35.1% to 7.1% for the left-side low-adhesion case and from 4.9% to 3.1% for the right-side low-adhesion case. These results demonstrate that the proposed controller can suppress excessive wheel slip while preserving the normal differential wheel-speed relationship required during cornering.

During the ISO 3888-2 double-lane-change test, the main and assist motor torques were adjusted according to the location of the low-adhesion surface. Although temporary wheel-speed disturbances occurred when the tires entered the low-adhesion regions, the wheel speeds converged without developing into sustained divergence. The results indicate that the proposed dual-input differential and traction control strategy can effectively reduce wheel slip under asymmetric and rapidly changing road conditions while maintaining the required wheel-speed relationship during consecutive steering maneuvers.

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