The electric vehicle (EV), compared with the gasoline car, has particular superiority benefiting from the in-vehicle electric motor. Vehicle motion control and many other vehicular applications like vibration-isolation control for the suspension system can realize satisfactory performance with cooperation of motor control. Since a controlled object, to achieve its optimum, relies on an appropriate control method, a control method based on reachability with fast convergence and strong robustness is adopted. Its efficiency is from two aspects:​ the inaccurate modelling is counted into unknown disturbance that will be estimated from an observer;​ and the designed system dynamics is planned from kinematics analysis in accordance with reachability. Hence, the method suppresses unknown disturbance and guarantees transient-state and steady-state performance. The thesis applies the reachability-based control method on the braking, motor and suspension systems to improve safety, efficiency and ride comfort.

Possibly short braking distance would be better for safety concern, which is determined by the friction force from the road. There is a maximal friction once the wheel reaches a state defined as the optimal slip ratio. However, the exact value of the state is usually unknown, thus conventional anti-lock braking system (ABS) only keeps the friction within a relatively high range but not at the summit. The thesis proposes a control system capable of online seeking the optimal slip ratio based on an extremum-seeking algorithm. The algorithm has high search rate and tolerance to noise. The controller designed by reachability-based control method can quickly and steadily realizing the command from the extremum-seeking algorithm, which contributes to high efficiency of the entire system. Numerical simulations sufficiently prove the proposed system can achieve the shortest braking distance, adaptive to different road conditions, compared with other systems.

The vehicle motion control cannot work well without satisfactory motor control. The interior permanent magnet synchronous machine (IPMSM) is a widely used motor in an EV. There is maximum torque per ampere (MTPA) operation for an IPMSM providing maximum efficiency, if ignoring iron loss. To calculate MTPA conditions in full operating range, the traditional equation assumes constant machine parameters, which lacks accuracy for a practical IPMSM. This thesis develops a modified equation based on the traditional equation by compensating the influence of varied machine parameters. To make the equation practical, the influence quantified as a lumped variable is not calculated from analytical definition but estimated by a proposed algorithm. The effectiveness of the proposed equation is verified by several IPMSMs where the data of machine parameters flows from finite-time element simulations. Another operation of the IPMSM is field-weakening control, when the motor is required working at high speed within voltage and current constraints of the supplied power. Conventional field-weakening control methods adjusting current or voltage phase angle based on feedbacks, focus on stability but lead to poor transient-state dynamics. A model-based method can solve the problem, but computational cost is considerable. Hence, the thesis adopts model-based method to calculate reference working point with availably maximal efficiency. Numerical computing methods are developed in terms of guaranteeing convergence and reducing computational cost. To further simplify calculation, a linear equation combining the MTPA point and maximum torque per voltage (MTPV) point is derived. To strengthen robustness, the adjustment strategies for different working points is developed to avoid chattering and instability. The validity and effectiveness of the proposed methods referring to MTPA control and field-weakening control are proved by numerical simulations and experiments.

Ride comfort profits from the suspension system mounted between the chassis and the wheel to isolate vibration from road unevenness, Convention active suspension system with controlled motor is adequate in improving ride comfort compared with traditional passive and semi-active suspension systems. However, the existed problem is that the required force from the motor should be large and quickly varied. Hence, an active suspension system with a particular structure is developed. The structure is inspired by a jack and drainage, based on the idea of release. The system consists of a rotational stick of which the two sides connecting a spring and a motor, which realizes large force by transferring into rotational motion. The stick has relative motion with the chassis, so that vibration energy can be discharged from the extra passageway. The fast response of the required force is realized by the control method based on reachability. Beneficial from it, the vibration energy will not be accumulated in the suspension system. Besides that, the proposed system can also realize other functions like height control to bring convenience to passengers. The simulation results prove the proposed suspension system with the designed controller can improve vibration-isolation performance compared with other control methods and suspension systems.