# A Review of Coordinated Control Technology for Chassis of Distributed Drive Electric Vehicles
## 4 Three-Dimensional Coordinated Control Strategies for DDEV Chassis  
In the field of coordinated chassis control for DDEVs, following significant progress in various two-dimensional (e.g., longitudinal-lateral, longitudinal-vertical) dynamic coordinated control strategies, the research focus has further expanded to integrated the coordinated control of lateral, longitudinal, and vertical (three-dimensional) aspects to achieve a more comprehensive improvement in overall vehicle dynamic performance. Currently, for such complex three-dimensional coordinated control problems, the adopted strategies can be mainly divided into two major technical directions: weight-based allocation (Figure 9) and optimization-based approaches (Figure 10). The core idea of weight-based allocation strategies for three-dimensional coordinated control lies in dynamically assigning weighting factors to the contributions of different control objectives (such as driving stability, ride comfort, path tracking accuracy) or actuators (such as steering system, drive/braking system, suspension system). These weighting factors are adaptively adjusted according to real-time varying vehicle states, driver intention, or the driving environment, aiming to achieve a refined comprehensive coordination of the vehicle's longitudinal, lateral, and vertical dynamics under complex and variable operating  
Figure 9: Three-dimensional lateral–longitudinal–vertical cooperative control based on weight allocation. conditions. The advantage of this strategy is that its control logic is relatively intuitive, and it exhibits a high execution efficiency under specific conditions. [PERSON] et al. [117] proposed a hierarchical control strategy to coordinate ASS, AFS, and DYC. In this architecture, the upper-layer controller calculates the total corrective yaw moment required by the vehicle and allocates this moment to the ASS and the middle-layer controller according to a preset linear weighting coefficient q, reflecting an initial weight division for vertical and lateral control actions in the top-level design. Subsequently, the middle-layer controller employs an adaptive fuzzy control method to dynamically coordinate the control actions of AFS and DYC according to different operating regions determined by real-time parameters such as wheel sideslip angle and tire-road friction force. This fuzzy logic-based adaptive adjustment achieves a more refined dynamic weight allocation or control priority adjustment. Finally, the lower-layer controller is responsible for accurately tracking the local control targets of the respective subsystems. Through this multi-level, multi-mechanism weight allocation and coordination, this strategy effectively achieves a coordinated control of longitudinal, lateral, and vertical dynamics, enhancing vehicles' lateral stability and vertical performance including ride comfort and trajectory tracking capability. Complementing the aforementioned strategies that focus on the continuous or fuzzy adaptive adjustment of weighting coefficients, coordinated control strategies based on mode switching achieve three-dimensional coordination by applying various preset control modes according to different vehicle states and driving conditions. Each mode typically corresponds to a specific set of weight allocation schemes or control priorities. [PERSON] et al. [118] proposed an integrated control strategy for braking, yaw, and roll that fuses mode switching with dynamic weights. This strategy adopts a hierarchical structure, wherein its monitoring layer dynamically divides the vehicle's operating state into four control modes based on vehicle yaw rate deviation and Time-to-Rollover (TTR) index: normal braking, braking-yaw integrated, braking-roll integrated, and braking-yaw-roll three-dimensionally integrated.