A playback device comprises an electroacoustic transducer; an acoustic waveguide in fluid communication with the transducer; and a housing delimiting an opening of the waveguide, the opening extending around an axis passing through the transducer. The opening may have a radial distance from the axis that varies with an azimuthal angle about the axis. An acoustic path length within the waveguide, between the transducer and the opening, is substantially constant and independent of azimuthal angle about the axis.

A playback device comprises an electroacoustic transducer; an acoustic waveguide in fluid communication with the transducer; and a housing delimiting an opening of the waveguide, the opening extending around an axis passing through the transducer. The opening may have a radial distance from the axis that varies with an azimuthal angle about the axis. An acoustic path length within the waveguide, between the transducer and the opening, is substantially constant and independent of azimuthal angle about the axis.

The disclosure relates to a method for freeing at least one locked wheel of a vehicle. One step of the method relates to identifying a locking scenario comprising the identification of the at least one locked wheel. A further method step is selecting a wheel freeing strategy being suitable for the identified locking scenario. Another step is directed to applying the selected wheel freeing strategy. Furthermore, the disclosure is directed to a propulsion system for a vehicle having at least one wheel. The propulsion system comprises at least one propulsion actuator. Moreover, at least one wheel speed sensor is provided, the wheel speed sensor being configured for detecting the rotational speed of the at least one wheel. Additionally, the propulsion system has at least one brake unit being configured for braking the at least one wheel and a control unit being configured for performing the above method.

A brake system may include an actuating device, in particular a brake pedal; a first piston-cylinder unit having two pistons subjecting the brake circuits to a pressure medium via a valve device, wherein one of the pistons can be actuated by the actuation device; a second piston-cylinder unit having an electric motor drive, a transmission at least one piston to supply at least one of the brake circuits with a pressure medium via a valve device; and a motor pump unit with a valve device to supply the brake circuits with a pressure medium. The brake system may also include a hydraulic travel simulator with a pressure or working chamber which is connected to the first piston-cylinder unit.

A method for adjusting brake pressures at pneumatically actuated wheel brakes of a vehicle includes receiving an external braking demand. The method further includes, in response to the received external braking demand, performing, during each of a plurality of computation cycles: (i) ascertaining control signals for pressure control valves of the pneumatically actuated wheel brakes of the vehicle, (ii) continuously ascertaining a differential slip value, wherein the differential slip value is a difference between a slip of two axles of the vehicle and is determined by measuring signals supplied by speed sensors of wheels of the vehicle, (iii) evaluating the differential slip value with respect to a predefined or adjustable setpoint differential slip value, (iv) based on the evaluation of the differential slip value, adapting the ascertained control signals, and (v) releasing the adapted control signals to the pressure control valves.

A drive control apparatus is applied to a drive system that is mounted to a vehicle, drives wheels of the vehicle by a motor, and brakes the wheels by a brake apparatus. The drive control apparatus determines a road-surface state of a travel road of the vehicle. The drive control apparatus suppresses slipping of the vehicle by correcting a drive torque by correcting at least either of a motor torque and a brake torque. When determined that the drive torque is to be corrected, the drive control apparatus adjusts a correction amount of the drive torque by adjusting the motor torque with higher priority than the brake torque in response to be determined that the road-surface state is rough.

A system calibrates a function of a tire friction of a vehicle traveling on a road from motion data including a sequence of control inputs to the vehicle that moves the vehicle on the road and a corresponding sequence of measurements of the motion of the vehicle moved by the sequence of control inputs. The system updates iteratively the probability distribution of the tire friction function until a termination condition is met, wherein, for an iteration, the system samples the probability distribution of the tire friction function, determines a state trajectory of the vehicle to fit the sequence measurements according to the measurement model and the sequence of control inputs according to the motion model including the sample of the tire friction function, and updates the probability distribution of the tire friction function based on the state trajectory of the vehicle.

A system calibrates a function of a tire friction of a vehicle traveling on a road from motion data including a sequence of control inputs to the vehicle that moves the vehicle on the road and a corresponding sequence of measurements of the motion of the vehicle moved by the sequence of control inputs. The system updates iteratively the probability distribution of the tire friction function until a termination condition is met, wherein, for an iteration, the system samples the probability distribution of the tire friction function, determines a state trajectory of the vehicle to fit the sequence measurements according to the measurement model and the sequence of control inputs according to the motion model including the sample of the tire friction function, and updates the probability distribution of the tire friction function based on the state trajectory of the vehicle.

A vehicle control system is configured to, when anti-skid control is started in a situation in which driving support control is being executed, execute a specific process for making a stop condition of the anti-skid control difficult to be satisfied as compared to when the driving support control is not being executed.

An overrunable test vehicle including an electronically-controlled anti-slip braking system for reducing wheel slip during rapid deceleration comprising: a chassis, at least one electric motor connected to a first axle, a hydraulic braking system connected with the chassis and at least a second axle, a rotational speed sensor for determining a rotational speed of a connected axle, a ground speed sensor, and a controller connected with the electric motor, the hydraulic braking system, the rotational speed sensor, and the ground speed sensor. The controller is configured to calculate a difference between the rotational speed of the axle and the ground speed of the chassis to determine a slip threshold of the wheels, actuate the hydraulic brake system to apply a first stopping force, control at least one motor parameter of the electric motor to apply a second stopping force. The first and second stopping forces combined are less than the slip threshold of the wheels such that the chassis rapidly decelerates free of a wheel slip condition.