Prior art — US Patent 8315769

Analysis of Prior Art Cited in U.S. Patent 8,315,769

During the examination of U.S. Patent 8,315,769 ('769 patent), the USPTO examiner cited several prior art references. The following analysis details the most relevant of these references and their potential impact on the patentability of the '769 patent's claims, particularly the independent claims 1, 9, and 21, which define the core invention related to an active suspension control system.

1. U.S. Patent No. 7,047,120 B2 (to Breed)

Full Citation: US 7,047,120 B2, "Arrangement to accurately measure vehicle motion and position," Inventor: David S. Breed, Assignee: Automotive Technologies International, Inc.
Dates: Filed: July 1, 2002; Issued: May 16, 2006.
Brief Description: Breed '120 discloses a system for accurately determining the motion and position of a vehicle. Crucially, it describes using a combination of accelerometers and gyroscopes (an "inertial measurement unit" or IMU) to measure vehicle accelerations. It explicitly teaches that the gyroscopes are used to determine the orientation of the accelerometers relative to the Earth's gravitational field. This allows the system to subtract the effects of gravity and inclination (e.g., being on a hill) to calculate the "true" or "absolute" acceleration of the vehicle in various axes, including lateral.
Potential Anticipation of '769 Claims:
- Claims 1, 9 (a), 21 (a): Breed '120 appears to teach the core concept of an "accelerometer-gyroscope for sensing an absolute lateral acceleration." The entire purpose of combining the two sensors in Breed '120 is to remove gravitational effects to get a true measure of the vehicle's acceleration, which is what the '769 patent defines as "absolute" acceleration. This reference provides a strong basis for anticipating the sensing element of the '769 claims.

2. U.S. Patent No. 6,470,265 B1 (to Hac)

Full Citation: US 6,470,265 B1, "Method and apparatus for controlling a vehicle suspension," Inventor: Aleksander Hac, Assignee: General Motors Corporation.
Dates: Filed: May 23, 2001; Issued: October 22, 2002.
Brief Description: Hac '265 describes a sophisticated vehicle suspension control system. It uses various sensors, including a lateral accelerometer and a yaw rate sensor (a type of gyroscope), to detect vehicle dynamics. The system processes these sensor inputs in a controller to actively adjust suspension components, such as dampers at each wheel, to improve handling and prevent rollover. It teaches controlling different parts of the suspension based on sensed vehicle motion.
Potential Anticipation of '769 Claims:
- Claims 1(b, c), 9(b, c, d), 21(b, c): Hac '265 discloses a controller ("apparatus") that receives signals based on lateral motion and sends control signals to individual suspension components. This maps directly onto the '769 patent's "suspension selector" and "plurality of controllers." Hac '265 describes a system where suspension characteristics are adjusted based on sensed lateral forces to improve performance, which aligns with the adjusting steps of claim 21. While it may not use the exact term "suspension selector," the function is present in its control logic.

3. U.S. Patent No. 6,650,985 B2 (to Hac et al.)

Full Citation: US 6,650,985 B2, "Rollover stability control for an automotive vehicle," Inventors: Aleksander Hac et al., Assignee: General Motors Corporation.
Dates: Filed: October 24, 2001; Issued: November 18, 2003.
Brief Description: This patent is also from the same assignee and lead inventor as Hac '265 and builds upon similar concepts. It specifically focuses on rollover prevention. The system uses a lateral accelerometer and a yaw rate sensor to calculate a "rollover index." Based on this index, a controller makes decisions to adjust vehicle systems, including active suspension components (like controllable anti-roll bars) and brakes, to counteract the tendency to roll over.
Potential Anticipation of '769 Claims:
- Claims 5, 13, 22: These dependent claims in the '769 patent specify that the purpose of the suspension adjustment is to move the center of gravity and more evenly distribute the load. Hac '985 directly addresses this by controlling suspension to maintain vehicle stability and prevent rollover, which inherently involves managing the vehicle's center of gravity and load distribution during cornering. This reference strengthens the argument that the purpose of the invention in '769 was already known in the art.

4. U.S. Patent No. 6,529,810 B2 (to Naito et al.)

Full Citation: US 6,529,810 B2, "Suspension control apparatus," Inventors: Gen Naito et al., Assignee: Toyota Jidosha Kabushiki Kaisha.
Dates: Filed: November 20, 2000; Issued: March 4, 2003.
Brief Description: Naito '810 discloses a suspension control apparatus that adjusts suspension damping force based on road surface conditions and vehicle behavior. It uses sensors for vertical acceleration and lateral acceleration to determine the appropriate control actions for the suspension system. The system is designed to distinguish between different driving scenarios (e.g., turning on a flat road vs. a banked road) and adjust the suspension actuators at the individual wheels accordingly.
Potential Anticipation of '769 Claims:
- Claims 1, 9, 21: Naito '810 teaches sensing lateral acceleration and using that data to adjust individual suspension characteristics. Like Hac '265, it discloses the fundamental feedback loop claimed in the '769 patent. The combination of Naito '810 (which shows the control loop) with Breed '120 (which shows how to get an "absolute" lateral acceleration reading) could be used to argue that the invention claimed in '769 would have been obvious to one of ordinary skill in the art.

Summary of Prior Art Impact

The combination of the cited references presents a significant challenge to the validity of the independent claims of the '769 patent.

Breed '120 teaches the use of an accelerometer-gyroscope combination to calculate absolute lateral acceleration, directly addressing the novel-sounding language in the preamble of claims 1, 9, and 21.
Hac '265, Hac '985, and Naito '810 all teach the core concept of a vehicle control system that senses lateral forces (using accelerometers and often yaw rate sensors) and sends signals to control individual components of the suspension system to improve performance, stability, and prevent rollover.

An argument under 35 U.S.C. § 102 (anticipation) could potentially be made if a single one of these references discloses every element of a claim. More likely, a strong argument under 35 U.S.C. § 103 (obviousness) exists: it would have been obvious to a person skilled in automotive engineering to take the "absolute" acceleration sensor from Breed '120 and use it as the input for the active suspension control systems described in the Hac or Naito patents. This is the likely basis for the "substantial new questions of patentability" found in the recent ex parte reexamination.