diff options
Diffstat (limited to 'backend/genesys/motor.h')
| -rw-r--r-- | backend/genesys/motor.h | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/backend/genesys/motor.h b/backend/genesys/motor.h new file mode 100644 index 0000000..d80da6d --- /dev/null +++ b/backend/genesys/motor.h @@ -0,0 +1,177 @@ +/* sane - Scanner Access Now Easy. + + Copyright (C) 2019 Povilas Kanapickas <povilas@radix.lt> + + This file is part of the SANE package. + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, + MA 02111-1307, USA. + + As a special exception, the authors of SANE give permission for + additional uses of the libraries contained in this release of SANE. + + The exception is that, if you link a SANE library with other files + to produce an executable, this does not by itself cause the + resulting executable to be covered by the GNU General Public + License. Your use of that executable is in no way restricted on + account of linking the SANE library code into it. + + This exception does not, however, invalidate any other reasons why + the executable file might be covered by the GNU General Public + License. + + If you submit changes to SANE to the maintainers to be included in + a subsequent release, you agree by submitting the changes that + those changes may be distributed with this exception intact. + + If you write modifications of your own for SANE, it is your choice + whether to permit this exception to apply to your modifications. + If you do not wish that, delete this exception notice. +*/ + +#ifndef BACKEND_GENESYS_MOTOR_H +#define BACKEND_GENESYS_MOTOR_H + +#include <cstdint> +#include <vector> +#include "enums.h" + +namespace genesys { + +/* Describes a motor acceleration curve. + + Definitions: + v - speed in steps per pixeltime + w - speed in pixel times per step. w = 1 / v + a - acceleration in steps per pixeltime squared + s - distance travelled in steps + t - time in pixeltime + + The physical mode defines the curve in physical quantities. We asssume that the scanner head + accelerates from standstill to the target speed uniformly. Then: + + v(t) = v(0) + a * t (2) + + Where `a` is acceleration, `t` is time. Also we can calculate the travelled distance `s`: + + s(t) = v(0) * t + a * t^2 / 2 (3) + + The actual motor slope is defined as the duration of each motor step. That means we need to + define speed in terms of travelled distance. + + Solving (3) for `t` gives: + + sqrt( v(0)^2 + 2 * a * s ) - v(0) + t(s) = --------------------------------- (4) + a + + Combining (4) and (2) will yield: + + v(s) = sqrt( v(0)^2 + 2 * a * s ) (5) + + The data in the slope struct MotorSlope corresponds to the above in the following way: + + maximum_start_speed is `w(0) = 1/v(0)` + + maximum_speed is defines maximum speed which should not be exceeded + + minimum_steps is not used + + g is `a` + + Given the start and target speeds on a known motor curve, `a` can be computed as follows: + + v(t1)^2 - v(t0)^2 + a = ----------------- (6) + 2 * s + + Here `v(t0)` and `v(t1)` are the start and target speeds and `s` is the number of step required + to reach the target speeds. +*/ +struct MotorSlope +{ + // initial speed in pixeltime per step + unsigned initial_speed_w = 0; + + // max speed in pixeltime per step + unsigned max_speed_w = 0; + + // maximum number of steps in the table + unsigned max_step_count; + + // acceleration in steps per pixeltime squared. + float acceleration = 0; + + unsigned get_table_step_shifted(unsigned step, StepType step_type) const; + + static MotorSlope create_from_steps(unsigned initial_w, unsigned max_w, + unsigned steps); +}; + +struct MotorSlopeTable +{ + std::vector<std::uint16_t> table; + unsigned steps_count = 0; + unsigned pixeltime_sum = 0; + + void slice_steps(unsigned count); +}; + +unsigned get_slope_table_max_size(AsicType asic_type); + +MotorSlopeTable create_slope_table(const MotorSlope& slope, unsigned target_speed_w, + StepType step_type, unsigned steps_alignment, + unsigned min_size, unsigned max_size); + +std::ostream& operator<<(std::ostream& out, const MotorSlope& slope); + + +struct Genesys_Motor +{ + Genesys_Motor() = default; + + // id of the motor description + MotorId id = MotorId::UNKNOWN; + // motor base steps. Unit: 1/inch + int base_ydpi = 0; + // maximum resolution in y-direction. Unit: 1/inch + int optical_ydpi = 0; + // slopes to derive individual slopes from + std::vector<MotorSlope> slopes; + + MotorSlope& get_slope(StepType step_type) + { + return slopes[static_cast<unsigned>(step_type)]; + } + + const MotorSlope& get_slope(StepType step_type) const + { + return slopes[static_cast<unsigned>(step_type)]; + } + + StepType max_step_type() const + { + if (slopes.empty()) { + throw std::runtime_error("Slopes table is empty"); + } + return static_cast<StepType>(slopes.size() - 1); + } +}; + +std::ostream& operator<<(std::ostream& out, const Genesys_Motor& motor); + +} // namespace genesys + +#endif // BACKEND_GENESYS_MOTOR_H |