Slip ratio

About: Slip ratio is a research topic. Over the lifetime, 2968 publications have been published within this topic receiving 57164 citations.

Impact of Effective Tire Radius on Wheel Slip Estimation and Antilock Brake System Performance of Heavy Road Vehicles

Abstract: The wheel slip ratio is a function of the longitudinal speed of the wheel center, angular wheel speed, and Effective Tire Radius (ETR). The longitudinal speed of the wheel center and angular wheel speed can be calculated/estimated using an accelerometer and wheel speed sensor. However, ETR has uncertainties owing to variation in vehicle mass, air pressure in the tire, and dynamic load transfer. This article firstly demonstrates the sensitivity of ETR on wheel slip estimation using a Fixed Radius Recursive Least Squares (FR-RLS) estimator and analyzes its effects on Antilock Brake System (ABS) performance. Secondly, it proposes a Radius Searching RLS (RS-RLS) wheel slip estimator that mitigates the drift in estimates, maintains vehicle stability, and improves ABS performance. The proposed method was evaluated on a Hardware-in-Loop system with IPG TruckMaker. The RS-RLS estimator based ABS algorithm was compared against three FR-RLS estimator based ABS algorithms having different values of ETR and was found to have one order of magnitude lower mean absolute error.

Wear prediction method of tire and computer program for wear prediction

Abstract: PROBLEM TO BE SOLVED: To provide a wear prediction method of a tire, capable of suppressing increase in labor.SOLUTION: A wear prediction method of a tire includes the steps of: creating an approximate model containing a ground contact area defined by a designated prescribed shape, regarding the ground contact surface of the tire to a road surface; setting a first approximate function related to shear stress of the slip area of the ground contact surface; setting a second approximate function related to a slip amount of the slip area of the ground contact area; acquiring resultant force of longitudinal force and lateral force acting on the tire; acquiring a slip ratio and a slip angle at the time when the longitudinal force and the lateral force act on the tire; acquiring average shear stress of the slip area on the basis of the first approximate function and the resultant force; acquiring the slip amount of the slip area on the basis of the second approximate function, the slip ratio and the slip angle; acquiring frictional energy on the ground contact surface on the basis of the average shear stress and the slip amount; and predicting wear of the tire on the basis of the acquired frictional energy.

Slip Ratio Control in Rail Vehicle Braking with Sliding Mode Control Method

Abstract: Wheel slide protection is the safe-related fundamental function for rail vehicle braking systems. The braking distance depends on the adhesion condition and the anti-skid controller's performance. In this paper, a sliding mode slip ratio control method was proposed based on online estimation of the tangential force between wheel and rail. Simulation results show that the estimator can estimate the tangential force with braking force and wheel's angular speed as inputs. And the actual slip ratio can track the reference value whether it is a constant or time-variant one. This method helps to control the sliding degree when wheelsets skidding during braking under degraded adhesion condition.

Simulation of the forced convection heat transfer non-newtonian nanofluid, aqueous solution of carboxymethyl cellulose-aluminum oxide, in slip flow regime through a microtube

Abstract: At present study the flow and heat transfer of Non-Newtonian nanofluid, aqueous solution of carboxymethyl cellulose-Aluminum oxide with different volume fractions of nano particles in a two dimensional microtube is simulated for the first time. Slip velocity and temperature jump boundary conditions are also considered along the microtube walls. The achieved results accuracy is investigated by comparison with those of previous data. The results are presented as isothermal contours, Nusselt number and the profiles of temperature and velocity at different cross sections of the microtube. It is observed that Nusselt number increases with slip velocity coefficient and volume fraction of nano particles; while its rate is more sensitive at higher values of Reynolds number.

Straight Driving Improvement of Mobile Robot Using Fuzzy/Current Sensor

Abstract: In this paper, the research was done focus on the driving efficiency improvement of mobile robot in outdoor environments. The slip is occurred during driving because dynamic characteristic of mobile robot and external environmental factors have an effect on the driving efficiency. For reducing the slip, researches have been done such as Optimal Slip Ratio Control and Model Following Control. But, reducing a slip has many difficulties such as disturbance, cumulative error of sensor, measurement imprecision. So, this paper proposed a robust ASS (Anti-Slip System) focus on the outdoor mobile robot. For reducing a slip, current sensor and encoder was used because current sensing and encoder has not cumulative error. Using the current sensing, designed the FSC (Fuzzy Slip Control), to complete the ASS (Anti Slip System) by combining PI. To demonstrate the control performance, real experiments are performed using the mobile robot in outdoor.