Abstract: An elastomeric seat bladder has upper and lower sheets of peripherally welded elastomeric material, and at least one of the upper and lower sheets of elastomeric material is sufficiently thick to effectively serve as an integral interface panel. In a first configuration, the lower sheet is formed of elastomeric material having a thickness in the range of 1 mm (0.04 inch) to 2.54 mm (0.100 inch), and the upper sheet is formed of elastomeric material having a thickness of approximately 0.375 mm (0.015 inch). In a second configuration, the relatively thick sheet of elastomeric material is utilized as the upper sheet of the bladder instead of the lower sheet; and in a third configuration, both upper and lower sheets of the bladder are formed of elastomeric material in the range of 1 mm (0.04 inch) to 2.54 mm (0.100 inch) in thickness.

Abstract: A capacitive load cell includes upper and lower capacitor plates and an intermediate array of dielectric pads formed of silicone-impregnated open-cell urethane foam (i.e., gel pads). The silicone essentially displaces air that would otherwise be trapped in the foam, contributing to a dielectric having minimal humidity-related variability. The upper capacitor plate is defined by an array of individual charge plates, the lower capacitor plate defines a ground plane conductor common to each of the charge plates, and the dielectric pads are disposed between the ground plane conductor and each of the charge plates, leaving channels between adjacent dielectric pads. When occupant weight is applied to the seat, the dielectric pads transmitting the weight distend laterally into the channels to reduce the separation between the respective upper and lower capacitor plates, and the consequent change in capacitance is detected as a measure of the applied force and the force distribution.

Abstract: A circuit board is inserted into an open-ended housing and potting material is dispensed onto the exposed face of the circuit board in a single step to seal the circuit board to the housing. One or more electrical interconnects such as a connector header or a ribbon cable attached to the circuit board extend upward through the potting material so that the potting material also forms an environmental seal around the electrical interconnects.

Abstract: The capacitance of a shielded capacitive load cell is determined so as to minimize the effect of stray or parasitic capacitance between the load cell and other objects including the shield. The load cell conductors are coupled across input and output terminals of an operational amplifier that is tied to a reference voltage. A constant current is applied to the load cell, and the resulting rate of change in voltage at the amplifier output is measured as a representation of the load cell capacitance. In a vehicle seat sensor application including an electromagnetic interference shield between the load cell and the seating surface, the amplifier output is coupled to the load cell electrode furthest from the shield, the amplifier maintains the other load cell electrode at a virtual reference voltage, and the shield is tied to the reference voltage.

Abstract: A frame-based occupant weight estimation apparatus for a vehicle seat that is supported by two or more floor brackets secured to the vehicle floor spans an open space between the floor brackets to prevent shunting of the occupant weight through a foreign object lying on the floor between the floor brackets. The weight estimation apparatus includes a fluid filled bladder sandwiched between first and second rigid plates, and is held in place between the seat frame and the floor brackets by a set of fasteners. A spring preloads the bladder so that deviations of the bladder fluid pressure from the preload pressure will be indicative of occupant weight. The first plate spans the open space between the floor brackets so that the fluid pressure is indicative of occupant weight even in cases where a portion of the occupant weight is supported by a foreign object disposed between the floor brackets.

Abstract: An occupant of a motor vehicle seat is characterized for purposes of air bag suppression based on the seated weight of the occupant, the variation of the seated weight, and the occupant's apparent longitudinal center-of-mass. The method distinguishes between an adult and a child seat, distinguishes between forward-facing and rearward-facing child seats, and detects cinching of a child seat.

Abstract: A torque-based occupant weight estimation apparatus for a vehicle seat includes front and rear torsion bars through which the seat frame is coupled to a set of floor brackets. The torsion bars are rotatably mounted on the floor brackets, and linkage arms rigidly coupled to opposing ends of each torsion bar are rotatably coupled to the seat frame so as to convert occupant seat weight into torsion bar torque. Torque sensors coupled to the torsion bars provide an indication of occupant weight.

Abstract: A seat frame-based occupant weight estimation load cell transfers the seat force to a floor bracket through a spherical ball and a ball actuator. The ball is in contact with the force sensor and has minimal contact area with either the ball actuator or the force sensor so that the transfer of forces not functionally related to occupant weight is minimized. The ball actuator is coupled to the seat frame, and a sensor bracket aligns the ball actuator with respect to the sensor. The sensor bracket is domed to securely anchor the seat to the floor bracket in the event of an inverse overload. A spring disposed between the ball actuator and the dome of the sensor bracket biases the ball against the force sensor to preload the force sensor for enabling off-loading detection.

Abstract: A frame-based occupant weight estimation apparatus for a vehicle seat that is supported by two or more floor brackets secured to the vehicle floor spans an open space between the floor brackets to prevent shunting of the occupant weight through a foreign object lying on the floor between the floor brackets. The weight estimation apparatus includes a fluid filled bladder sandwiched between first and second rigid plates, and is held in place between the seat frame and the floor brackets by a set of fasteners. A spring preloads the bladder so that deviations of the bladder fluid pressure from the preload pressure will be indicative of occupant weight. The first plate spans the open space between the floor brackets so that the fluid pressure is indicative of occupant weight even in cases where a portion of the occupant weight is supported by a foreign object disposed between the floor brackets.

Abstract: A child seat anchor apparatus includes at least one sensor for measuring tension exerted on a system including a pair of anchor brackets disposed between the bottom and back cushions of a vehicle seat. In a first mechanization, the anchor brackets are directly coupled to individual sensors mounted on an anchor frame that is bolted to the seat frame. In a second mechanization, the anchor brackets are fastened to an anchor frame that is pivotably mounted on the seat frame, and the anchor frame is additionally coupled to the seat frame through a single sensor responsive to the tension exerted on the anchor frame by the anchor brackets.

Abstract: In a vehicle seat occupant detection system, a transponder in a seat cushion is responsive to an activating signal to generate an electromagnetic signal containing unique seat identification data. An occupant detection system module senses a seat characteristic and derives therefrom an occupant detection signal. The module further generates the transponder activating signal and receives and processes the electromagnetic signal to derive the contained seat identification data. The module determines if there is seat identification data in a dedicated memory location in rewritable, non-volatile memory and, if there is, compares it to the seat identification data from the electromagnetic signal. If they do not match, the derivation of a valid occupant detection signal is prevented.

Abstract: An improved weight-based occupant characterization method reliably distinguishes between a minimum weight adult and a child seated on a booster seat. An early characterization of the seat occupant is made in an interval following a transition event such as a door opening or ignition state change that activates the occupant detection system. During this interval, an initial characterization routine monitors the seat belt tension and the raw seat pressure to identify signal values characteristic of a minimum weight adult or a child seated on a booster seat. If the indicated occupant weight during subsequent operation of the vehicle is inconsistent with the initial characterization, the initial characterization is discarded, and the seat occupancy is characterized based on the indicated occupant weight.

Abstract: In a vehicle seat occupant detection system, a transponder in a seat cushion is responsive to an activating signal to generate an electromagnetic signal containing unique seat identification data. An occupant detection system module senses a seat characteristic and derives therefrom an occupant detection signal. The module further generates the transponder activating signal and receives and processes the electromagnetic signal to derive the contained seat identification data. The module determines if there is seat identification data in a dedicated memory location in rewritable, non-volatile memory and, if there is, compares it to the seat identification data from the electromagnetic signal. If they do not match, the derivation of a valid occupant detection signal is prevented.

Abstract: An improved weight-based occupant characterization method reliably distinguishes between a minimum weight adult and a child seated on a booster seat. An early characterization of the seat occupant is made in an interval following a transition event such as a door opening or ignition state change that activates the occupant detection system. During this interval, an initial characterization routine monitors the seat belt tension and the raw seat pressure to identify signal values characteristic of a minimum weight adult or a child seated on a booster seat. If the indicated occupant weight during subsequent operation of the vehicle is inconsistent with the initial characterization, the initial characterization is discarded, and the seat occupancy is characterized based on the indicated occupant weight.

Abstract: An improved vehicle seat occupant weight estimation method detects weight applied to both the seat cushion and the floor forward of the seat, and increases the measured seat weight of the occupant to account for occupant weight off-loaded to the floor. Fluid-filled bladders or other sensors are arranged to detect occupant seat weight and the weight applied to the vehicle floor forward of the seat. Upon opening of a vehicle door or an off-to-on transition of the vehicle ignition switch, the seat and floor weight sensors are monitored to detect the presence of an occupant. When the seat becomes occupied, or whenever there is a large change in the measured seat weight, the seat and floor weight are recorded, the occupant weight is estimated according to the recorded seat weight, and the inflatable restraints are allowed or suppressed based on the estimated occupant weight.

Abstract: An improved occupant detection system and method includes a fluid-filled polymeric seat cushion bladder defining multiple fluid-filled chambers corresponding to different areas of the seat cushion, with no fluid flow between such chambers. Fluid pressures in the various individual chambers are detected and processed to develop a weight estimation that is compensated for occupant position. The chambers are configured to detect occupant weight in at least forward, rearward, inboard and outboard regions of the bottom seat cushion. When the detected pressures are unevenly distributed and the pressure in the forward, rearward, inboard or outboard regions of the seat exceeds the average pressure by at least a predetermined amount, a composite pressure indicative of occupant weight is adjusted in a direction to bias the suppression status in favor of allowing restraint deployment, unless the occupant is forwardly positioned on a seat that is also forwardly positioned.

Abstract: An improved occupant detection system and method includes a fluid-filled polymeric seat cushion bladder defining multiple fluid-filled chambers corresponding to different areas of the seat cushion, with no fluid flow between such chambers. Fluid pressures in the various individual chambers are detected and processed to develop a weight estimation that is compensated for occupant position. The chambers are configured to detect occupant weight in at least forward, rearward, inboard and outboard regions of the bottom seat cushion. When the detected pressures are unevenly distributed and the pressure in the forward, rearward, inboard or outboard regions of the seat exceeds the average pressure by at least a predetermined amount, a composite pressure indicative of occupant weight is adjusted in a direction to bias the suppression status in favor of allowing restraint deployment, unless the occupant is forwardly positioned on a seat that is also forwardly positioned.

Abstract: An improved weight-based occupant characterization method reliably distinguishes between a child or small adult and a tightly cinched child seat based on a variance in the sensed occupant weight and a variance in the vehicle acceleration. The weight variance and acceleration variance are used to determine a relative or normalized variance that compensates for the effects of operating the vehicle on a rough road surface. The occupant is characterized as a child seat if the normalized variance is below a first threshold for a predetermined interval, and as a child or small adult if the normalized variation exceeds a second threshold for a predetermined interval.

Abstract: An improved weight-based occupant characterization method reliably distinguishes between a child or small adult and a tightly cinched child seat based on a variance in the sensed occupant weight and a variance in the vehicle acceleration. The weight variance and acceleration variance are used to determine a relative or normalized variance that compensates for the effects of operating the vehicle on a rough road surface. The occupant is characterized as a child seat if the normalized variance is below a first threshold for a predetermined interval, and as a child or small adult if the normalized variation exceeds a second threshold for a predetermined interval.