S7RTT is a lightweight, high-performance C++/C/Python/ST library designed for generating 7-segment S-curve motion profiles (jerk-limited trajectories).

While conceptually similar to the renowned Ruckig library, S7RTT is specifically optimized for single-axis applications, offering a streamlined alternative for embedded systems and real-time control loops where low latency and deterministic execution are paramount.

S7RTT provides a robust solution for time-optimal trajectory generation with the following capabilities:

• Arbitrary Initial State: Calculate trajectories starting from any position, velocity, and acceleration.
• Target State Control: Reach any desired target position and velocity.
  • Note: The target acceleration is fixed at 0 and cannot be modified in the current version.
• Full Jerk Constraints: Implements complete jerk limitation to ensure smooth, third-order continuous motion, reducing mechanical stress.
• Real-Time Interruption: Supports "online" trajectory generation. You can interrupt the motion at any time with new target parameters, and the library will calculate a smooth transition from the current kinematic state.

S7RTT is not intended to replace Ruckig for multi-DOF or complex non-zero target acceleration cases, but it offers distinct advantages in specific single-axis scenarios:

1. Standard Trajectories: For normal point-to-point moves, calculation results are consistent with Ruckig.
   
2. Velocity Limits: S7RTT demonstrates superior trajectory optimization when handling cases where the maximum velocity limit is dynamically lowered or constrained.
   
3. Boundary Conditions:
   • In many edge cases, performance is comparable.
     
   • Ruckig currently maintains an edge in robustness regarding specific complex mathematical boundary singularities.
     

Benchmarks conducted on C++ platforms highlight the efficiency of S7RTT:

• Faster Computation: S7RTT requires significantly less CPU time per calculation cycle compared to Ruckig.
• Lower Jitter: The calculation time is more deterministic with lower variance (jitter), making it highly suitable for hard real-time systems where timing budgets are strict.

(Measure cycle time compare chart, The unit is nanoseconds)

S7RTT aims to provide a simple, fast, and reliable trajectory generator for single-axis motion control tasks. By simplifying the problem space (fixing target acceleration to zero), it achieves extremely high performance and code simplicity.

Special thanks to Gemini 3 Pro for the assistance in the development and optimization of this library.