GimbalLock

Gimbal lock is a phenomenon in orientation representation that occurs when a system using a triple-gimbal mechanism loses one degree of freedom, typically because two of the gimbals become aligned. This loss happens most often when using Euler angles to describe attitude, such as a yaw-pitch-roll sequence (z-y-x). When the pitch angle approaches ±90 degrees, the yaw and roll axes align and rotate about the same axis, making it impossible to distinguish or independently control those two components.

In practical terms, gimbal lock means the attitude cannot be uniquely determined from the three angles, and small changes in one angle can produce large, coupled changes in the others. This can lead to ill-conditioned attitude estimation and control problems in navigation, robotics, aerospace, and virtual reality systems.

The term originates from mechanical gimbals used to stabilize devices like compasses and cameras. The lock is a mathematical singularity of Euler angle representations rather than a physical failure of the joints themselves.

Mitigation approaches include using alternative orientation representations that do not suffer from the same singularities, such as quaternions or rotation matrices. Quaternions, in particular, provide a four-parameter, non-singular description of rotation that avoids gimbal lock. Practically, systems may also constrain motion to avoid near-90-degree pitch, or implement sensor fusion and numerical methods that handle near-singular configurations.