1c141a5.bug

%YAML 1.1
---
id: 1c141a5
title: Unexpected Movement Due to Wrong Calculation
description: >
  Kobuki moves using differential drive. Originally, the command
  velocities (linear and angular) were provided as `short`, and
  were converted to `short` after each step, even though the
  calculations yielded floating point numbers.
  This lead to calculation errors in some special cases, where the
  robot was supposed to move forward but ended up moving backwards
  instead.
classification: "CWE-704: Incorrect Type Conversion or Cast #PHYSICAL"
keywords: ['differential drive', 'rounding', 'driver', 'movement']
system: kobuki
severity: error
links: ['https://en.wikipedia.org/wiki/Differential_wheeled_robot']
bug:
  phase: runtime
  specificity: robotics-specific
  architectural-location: application-specific code
  application: mobile robot
  task: differential drive
  subsystem: driver
  package: yujinrobot/kobuki/kobuki_driver
  languages:
    - C++
  detected-by: developer
  reported-by: contributor
  issue: https://github.com/yujinrobot/kobuki/issues/246
  time-reported: 2013-04-05T09:27:36Z
  reproducibility: always
  trace: null
fix:
  pull-request: null
  fix-in: ['kobuki_driver/include/kobuki_driver/modules/diff_drive.hpp', 'kobuki_driver/src/driver/diff_drive.cpp']
  languages:
    - C++
  time: 2013-05-07 (06:40)
  commits:
    - repo: https://github.com/yujinrobot/kobuki
      hash: 1c141a54fb2c0e2ec453b32f8026d1cd0ffb14d9
      stats:
        total:
          insertions: 25
          deletions: 15
          lines: 40
          files: 2
        files:
          kobuki_driver/include/kobuki_driver/modules/diff_drive.hpp:
            insertions: 6
            deletions: 2
            lines: 8
          kobuki_driver/src/driver/diff_drive.cpp:
            insertions: 19
            deletions: 13
            lines: 32
fault-codes:
  - PROGRAMMING:DATATYPE
  - PROGRAMMING:CALCULATIONS
failure-codes:
  - SOFTWARE:BEHAVIORAL
  - SYSTEM:BEHAVING-INCORRECTLY